Keyword  Type  Description 
BS_KPOINT_PATH  Block  Kpoint path for bandstructure calculation 
CHARGE  Integer  Total charge of system 
CLASSICAL_INFO  Block  Include classical point charges in the system 
COND_CALC_MAX_EIGEN  Logical  Calculate maximum conductionHamiltonian eigenvalue at each NGWF CG optimisation step. 
COND_CALC_OPTICAL_SPECTRA  Logical  Calculate matrix elements for use in optical absorption spectra 
COND_ENERGY_GAP  Physical  Energy gap between highest optimised and lowest unoptimised cond state 
COND_ENERGY_RANGE  Physical  Energy range of optimised cond states measured from HOMO 
COND_FIXED_SHIFT  Logical  Keep shift for projected conduction Hamiltonian constant in COND task 
COND_INIT_SHIFT  Physical  Initial shifting factor for projected conduction Hamiltonian. 
COND_KERNEL_CUTOFF  Physical  Conduction state density kernel cutoff radius in bohr. 
COND_MAXIT_LNV  Integer  Maximum number of LNV iterations during conductionNGWF optimisation. 
COND_MINIT_LNV  Integer  Minimum number of LNV iterations during conduction NGWF optimisation. 
COND_NUM_STATES  Logical  The number of conduction states to be optimised. 
COND_PLOT_JOINT_ORBITALS  Logical  Plot orbitals in joint valenceconduction basis following COND task 
COND_PLOT_VC_ORBITALS  Logical  Plot orbitals in separate val cond bases following COND task 
COND_READ_DENSKERN  Logical  Read in the conduction density kernel from disk 
COND_READ_TIGHTBOX_NGWFS  Logical  Read in the conduction NGWFs from disk 
COND_SHIFT_BUFFER  Physical  Buffer added to the highest calculated eigenvalue when updating the conduction shift 
COND_SPEC_CALC_MOM_MAT_ELS  Logical  Calculate optical matrix elements in momentum representation 
COND_SPEC_CALC_NONLOC_COMM  Logical  Calculate commutator between nonlocal potential and position operator 
COND_SPEC_CONT_DERIV  Logical  Calculate commutator between the nonlocal potential and position operator using continuous derivative in kspace 
COND_SPEC_NONLOC_COMM_SHIFT  Real  Finite difference shift for calculating commutator between nonlocal potential and the position operator (if calculated using finite differences) 
CONSTANT_EFIELD  Text  Constant electric field to be applied 
CUBE_FORMAT  Logical  Use cube format for plot files 
CUTOFF_ENERGY  Physical  Equivalent plane wave kinetic energy cutoff 
DBL_GRID_SCALE  Real  Ratio of charge density / potential working grid to standard grid (1 or 2 only). 
DDEC_CALCULATE  Logical  Run DDEC analysis. 
DDEC_CLASSICAL_HIRSHFELD  Logical  Output results from classical Hirshfeld partitioning 
DISPERSION  Integer  Activate dispersion corrections 
DO_PROPERTIES  Logical  Permit calculation of properties 
DX_FORMAT  Logical  Use OpenDX format for plot files 
EDFT  Logical  Enable finitetemperature DFT calculations with the EnsembleDFT method 
EDFT_INIT_MAXIT  Integer  Maximum number of inner loop iterations with the EDFT method to be performed at the start of the calculation. 
EDFT_MAXIT  Integer  Maximum number of inner loop iterations with the EDFT method. 
EDFT_SMEARING_WIDTH  Physical  Occupation smearing width for EDFT calculations. 
EDFT_SPIN_FIX  Integer  Number of NGWF CG iterations to hold the spin fixed. If negative, hold forever. 
ELD_CALCULATE  Logical  Calculate electron localisation descriptors 
ELD_FUNCTION  Text  Choose which electron localisation descriptor to use during the properties calculation, either ELF or LOL 
ETRANS_BULK  Logical  Compute the bulk transmission coefficients of the individual leads defined in ETRANS_LEADS. 
ETRANS_EMAX  Physical  Highest energy for the calculation of the transmission coefficients. 
ETRANS_EMIN  Physical  Lowest energy for the calculation of the transmission coefficients 
ETRANS_ENUM  Integer  Number of energy steps for the calculation of the transmission coefficients 
ETRANS_LCR  Logical  Compute the 'LeftCentreRight' transmission coefficients between all leads defined in ETRANS_LEADS . 
ETRANS_LEADS  Block  Defines the atoms that form the leads for the calculation of the transport coefficients. 
ETRANS_SETUP  Block  Transport setup description 
EXTERNAL_PRESSURE  Physical  Value of the input pressure Pin in the electronic enthalpy functional H=U+PV, 
FINE_GRID_SCALE  Real  Spacing of fine grid as multiple of standard grid 
GEOM_LBFGS  Logical  Whether to perform LBFGS rather than BFGS in a Geometry Optimization 
GEOM_MAX_ITER  Integer  Maximum number of geometry optimisation iterations 
GEOM_METHOD  Text  Geometry optimisation method 
GEOM_PRECOND_TYPE  Text  Which preconditioner to use for the LBFGS geometry optimiser 
GRD_FORMAT  Logical  Use.grdformat for plot files 
HOMO_DENS_PLOT  Integer  Number of canonical orbital densities to plot below HOMO 
HOMO_PLOT  Integer  Number of canonical orbitals to plot below HOMO 
HUBBARDSCF_ON_THE_FLY  Logical  Activate a nonvariational onthefly form of projector selfconsistency in DFT+U or cDFT, in which the projectors are updated whenever the NGWFs are. task : HUBBARDSCF is then not needed. 
HUBBARD_CONV_WIN  Integer  The minimum number of Hubbard projector update steps satisfying the incremental energy tolerance hubbard_energy_tol required for convergence in task : HUBBARDSCF. 
HUBBARD_ENERGY_TOL  Physical  The maximum incremental energy change between Hubbard projector update steps allowed for converge in task : HUBBARDSCF. 
HUBBARD_FUNCTIONAL  Integer  The form of DFT+U energy term used. 
HUBBARD_MAX_ITER  Integer  The maximum allowed number of Hubbard projector update steps taken in a projector selfconsistent DFT+U or cDFT calculation in task : HUBBARDSCF. 
HUBBARD_NGWF_SPIN_THRESHOLD  Physical  The incremental change in energy, in totalenergy minimisation, at which any spinsplitting (Zeeman) type term in DFT+U is switched off, and the minimisation history reset. 
HUBBARD_PROJ_MIXING  Real  The fraction of previous Hubbard projector to mix with new for projector selfconsistent DFT+U or cDFT in task : HUBBARDSCF. Not found to be necessary. 
HUBBARD_READ_PROJECTORS  Logical  Read Hubbard projectors from .tightbox_hub_projs file in restart calculations involving DFT+U. 
HUBBARD_TENSOR_CORR  Integer  The form of correction used to correct for any nonorthogonality between Hubbard projectors. 
IS_BULK_PERMITTIVITY  Real  Defines the relative dielectric permittivity of the solvent 
IS_IMPLICIT_SOLVENT  Logical  Makes the calculation use implicit solvent 
IS_INCLUDE_APOLAR  Logical  Turns on the apolar term (cavitation, solutesolvent dispersionrepulsion) in an implicit solvent calculation 
IS_INCLUDE_CAVITATION  Logical  KEYWORD REPLACED BY IS_INCLUDE_APOLAR in v4.4.6 (main branch) and v4.5.1 (devel branch). Turns on the cavitation term in an implicit solvent calculation 
IS_SOLVENT_SURFACE_TENSION  Physical  Used to define the surface tension of the solvent, NOW SUPERSEDED BY IS_SOLVENT_SURF_TENSION (with a change in meaning). DO NOT USE THIS KEYWORD ANYMORE. 
IS_SOLVENT_SURF_TENSION  Physical  Defines the surface tension of the solvent. This keyword supersedes IS_SOLVENT_SURFACE_TENSION (but has a different meaning, see doc). 
KERNEL_CHRISTOFFEL_UPDATE  Logical  Preserve the densitymatrix (idempotency, norm) to first order when the NGWFs change. 
KERNEL_CUTOFF  Physical  Density kernel cutoff radius. 
KE_DENSITY_CALCULATE  Logical  Calculate kinetic energy density 
LATTICE_CART  Block  Simulation cell lattice vectors in Cartesian coordinates 
LUMO_DENS_PLOT  Integer  Number of canonical orbital densities to plot above LUMO 
LUMO_PLOT  Integer  Number of canonical orbitals to plot above LUMO 
MD_DELTA_T  Physical  Molecular dynamics time step 
MD_NUM_ITER  Integer  Number of molecular dynamics iterations 
MD_RESET_HISTORY  Integer  Full reset of the NGWFs and density kernel SCF cycle every N MD steps. New initial guesses for the electronic degrees of freedom are built according to COREHAM_DENSKERN_GUESS and SPECIES_ATOMIC_SET .

MD_RESTART  Logical  Restart MD from previous backup files 
NBO_LIST_PLOTNBO  Block  The list of NBO_PLOT_ORBTYPE orbitals to be plotted. 
NBO_PLOT_ORBTYPE  Text  The type of gennbogenerated orbitals to read and plot. 
NBO_WRITE_DIPOLE  Logical  Computes and writes dipole matrix to FILE.47 
NBO_WRITE_NPACOMP  Logical  Writes NAO charges for all orbitals to standard output. 
NBO_WRITE_SPECIES  Block  Block of lists of species to be included in the partial matrix output of seedname_nao_nbo.47. 
NNHO  Logical  Convert NGWFs into nonorthogonal natural hybrid orbitals 
OUTPUT_DETAIL  Text  Specify level of output detail 
PAW  Logical  Activate PAW calculation. 
PHONON_ANIMATE_LIST  Block  List of Gammapoint modes (where 1 is the lowest) for which to write xyz animation files. 
PHONON_ANIMATE_SCALE  Real  Relative scale of the amplitude of the vibration in the xyz animation. 
PHONON_DELTAT  Physical  Temperature step for the computation of thermodynamic quantities. 
PHONON_DISP_LIST  Block  List of force constant calculations to perform for Stage 2 in phonon calculations (i.e. in the case of phonon_farming_task 2 or 0). 
PHONON_DOS  Logical  Calculate the phonon DOS and write to file. 
PHONON_DOS_DELTA  Real  Frequency step for the phonon DOS calculation (in 1/cm). 
PHONON_DOS_MAX  Real  Upper bound of the phonon DOS range (in 1/cm). 
PHONON_DOS_MIN  Real  Lower bound of the phonon DOS range (in 1/cm). 
PHONON_ENERGY_CHECK  Logical  Perform a sanity check that the total energy does not decrease upon ionic displacement. 
PHONON_EXCEPTION_LIST  Block  List of exceptions to the global defaults defined by PHONON_VIB_FREE , PHONON_SAMPLING , and PHONON_FINITE_DISP . 
PHONON_FARMING_TASK  Integer  Select which phonon calculation stage to perform. Can be either 1,2,3 for a single stage, or 0 for all stages. Default is 0. 
PHONON_FINITE_DISP  Physical  Ionic displacement distance. 
PHONON_FMAX  Physical  Maximum ionic force allowed in the unperturbed system. 
PHONON_GRID  Block  Definition of the regular grid of qpoints used in phonon calculations for the computation of thermodynamic quantities and the phonon DOS. 
PHONON_MIN_FREQ  Physical  Minimum phonon frequency for the computation of thermodynamic quantities, expressed as an energy; frequencies lower than this are discarded. 
PHONON_QPOINTS  Block  List of additional qpoints for which to calculate the phonon frequencies, in fractional coordinates of the reciprocal unit cell vectors. 
PHONON_SAMPLING  Integer  Selects which finitedifference formula to use. 
PHONON_SK  Logical  Use a SlaterKoster style interpolation for qpoints instead of a realspace cutoff of the force constants matrix elements. 
PHONON_TMAX  Physical  Upper bound of the temperature range for the computation of thermodynamic quantities. 
PHONON_TMIN  Physical  Lower bound of the temperature range for the computation of thermodynamic quantities, expressed as an energy (k_B T). 
PHONON_VIB_FREE  Integer  Default allowed vibrational degrees of freedom for all ions. 
PHONON_WRITE_EIGENVECS  Logical  Write the eigenvectors as well as the phonon frequencies to file for the additional qpoints. 
PLOT_NBO  Logical  Instructs ONETEP to read the relevant orbital transformation output from gennbo, determined by the flag NBO_PLOT_ORBTYPE and plots the orbitals specified in the NBO_LIST_PLOTNBO block. 
POLARISATION_CALCULATE  Logical  Activate Polarisation Calculation 
POPN_BOND_CUTOFF  Physical  Mulliken population analysis bond length cutoff 
POPN_CALCULATE  Logical  Perform Mulliken population analysis 
POSITIONS_ABS  Block  Atomic positions in Cartesian coordinates 
READ_DENSKERN  Logical  Read density kernel to restart 
READ_SW_NGWFS  Logical  Read NGWFS in spherical waves format to restart 
READ_TIGHTBOX_NGWFS  Logical  Read NGWFs to restart 
RMS_KERNEL_MEASURE  Logical  Use a legacy measure of the commutator of the densitymatrix and Hamiltonian, given by the root mean squared value of the doublycovariant NGWF representation of their commutator. 
SPECIES  Block  Atomic species information 
SPECIES_COND  Block  Atomic species information for conduction NGWFs 
SPECIES_CONSTRAINTS  Block  Atomic species geometry optimisation constraints 
SPECIES_LDOS_GROUPS  Block  Local Density of States species group definitions 
SPECIES_NGWF_PLOT  Block  Atomic species for plotting NGWFs 
SPECIES_POT  Block  Pseudopotentials for atomic species 
SPIN  Integer  Total spin of system 
SPIN_POLARIZED  Logical  Perform spin polarized calculation 
SPREAD_CALCULATE  Logical  Activate Calculation of NGWF Spreads 
SUPERCELL  Block  Definition of the supercell used for crystalline materials in phonon calculations. 
TASK  Text  Specify task 
THREADS_MAX  Integer  Number of threads in outer loops. 
THREADS_NUM_FFTBOXES  Integer  Number of threads to use in OpenMPparallel FFTs. 
THREADS_NUM_MKL  Integer  The number of threads to use in MKL routines (matrixmatrix multiplications, inverses, diagonalisations etc.). 
WRITE_DENSITY_PLOT  Logical  Write out charge density and electrostatic potential for plotting 
WRITE_DENSKERN  Logical  Write density kernel for future restart 
WRITE_FORCES  Logical  Include ionic forces in output 
WRITE_NBO  Logical  Enables Natural Population Analysis (NPA) and writing of gennbo input file seedname_nao_nbo.47 
WRITE_NGWF_PLOT  Logical  Write out NGWFs for plotting 
WRITE_SW_NGWFS  Logical  Write NGWFs in spherical waves format for future restart 
WRITE_TIGHTBOX_NGWFS  Logical  Write NGWFs for future restart 
WRITE_XYZ  Logical  Write .xyz file of atom coordinates for visualisation 
XC_FUNCTIONAL  Text  Exchangecorrelation functional 
Keyword  Type  Description 
BSUNFLD_KPOINT_PATH  Block  Kpoint path for bandstructure unfolding calculation 
BSUNFLD_TRANSFORMATION  Integer  Transformation matrix (flattened) between primitivecell and supercell lattice vectors when unfolding bandstructure 
BS_KPOINT_PATH_SPACING  Physical  Kpoint spacing along the bandstructure path 
BS_METHOD  Text  Which method to use for the calculation of bandstructures 
BS_NUM_EIGENVALUES  Integer  Number of energy eigenvalues to print in a bandstructure calculation 
CDFT_ATOM_CHARGE  Logical  Activate atom chargeconstrainedDFT mode. This mode is incompatible with any other cDFTmode. 
CDFT_ATOM_SPIN  Logical  Activate atom magneticmomentconstrainedDFT mode. This mode is incompatible with any other cDFTmode. 
CDFT_CG_THRESHOLD  Real  Specifies the convergence threshold for the RMS gradient of the constraining potentials (Uq/s). 
CDFT_CHARGE_ACCEPTOR_TARGET  Real  Targeted acceptorgroup electron population for acceptorgroup chargeconstrainedDFT mode [CDFT_GROUP_CHARGE_ACCEPTOR = T].

CDFT_CHARGE_DONOR_TARGET  Real  Targeted donorgroup electron population for donorgroup chargeconstrainedDFT mode [CDFT_GROUP_CHARGE_DONOR = T]

CDFT_CONTINUATION  Logical  Continue a constraining potential (Uq/s) optimisation from a previous run using the .cdft file with the latest cDFTpotentials. 
CDFT_ELEC_ENERGY_TOL  Physical  Tolerance on energy change per atom during CDFT optimisation. If negative, the option is deactivated. 
CDFT_GROUP_CHARGE_ACCEPTOR  Logical  Activate acceptorgroup chargeconstrainedDFT mode. 
CDFT_GROUP_CHARGE_DIFF  Logical  Activate group chargedifference constrainedDFT mode. 
CDFT_GROUP_CHARGE_DIFF_TARGET
 Real  Targeted electron population difference between acceptor and donor group for groupchargedifference constrainedDFT mode [CDFT_GROUP_CHARGE_DIFF =T]. 
CDFT_GROUP_CHARGE_DONOR  Logical  Activate donorgroup chargeconstrainedDFT mode. 
CDFT_GROUP_CHARGE_DOWN_ONLY
 Logical  Constrain only SPINDOWN channel in CDFT_GROUP_CHARGE_ACCEPTOR , CDFT_GROUP_CHARGE_DONOR and CDFT_GROUP_CHARGE_DIFF modes. 
CDFT_GROUP_CHARGE_UP_ONLY
 Logical  Constrain only SPINUP channel in CDFT_GROUP_CHARGE_ACCEPTOR , CDFT_GROUP_CHARGE_DONOR and CDFT_GROUP_CHARGE_DIFF modes. 
CDFT_GROUP_SPIN_ACCEPTOR
 Logical  Activate acceptorgroup magneticmoment constrainedDFT mode. 
CDFT_GROUP_SPIN_DIFF
 Logical  Activate group magneticmomentdifference constrainedDFT mode. 
CDFT_GROUP_SPIN_DIFF_TARGET
 Real  Targeted magneticmoment difference between acceptor and donor group for groupmagneticmomentdifference constrainedDFT mode [CDFT_GROUP_SPIN_DIFF =T]. 
CDFT_GROUP_SPIN_DONOR  Logical  Activate donorgroup magneticmoment constrainedDFT mode. 
CDFT_HUBBARD  Logical  Activate the constrainedDFT+U functionality. It requires specifications of a positive value for the Hubbard correction (Uh) in the CONSTRAINED_DFT Block. 
CDFT_MAX_GRAD
 Real  Specifies the convergence threshold for the maximum value of the constrainingpotential (Uq/s) gradient at any cDFTsite. 
CDFT_MULTI_PROJ
 Logical  Activate the “as many cDFTprojectors as NGWFs” cDFTmode. 
CDFT_PRINT_ALL_OCC  Logical  Print detailed information of occupancies for al the cDFTsites, for OUTPUT_DETAIL = VERBOSE.

CDFT_READ_PROJ  Logical  Read cDFTprojectors from .tightbox_hub_proj file. 
CDFT_SPIN_ACCEPTOR_TARGET
 Real  Targeted group magneticmoment for acceptorgroup magneticmoment constrainedDFT mode [CDFT_GROUP_SPIN_ACCEPTOR = T]. 
CDFT_SPIN_DONOR_TARGET  Real  Targeted group magneticmoment for donorgroup magneticmoment constrainedDFT mode [CDFT_GROUP_SPIN_DONOR = T]. 
CDFT_TRIAL_LENGTH  Real  Specifies initial trial length for first step of constrainingpotential (Uq/s) conjugate gradients optimisation. 
CI_CDFT
 Logical  Perform a Configuration Interaction calculation based on constrainedDFT configurations. 
CI_CDFT_NUM_CONF  Integer  Specifies the number of constrainedDFT configuration available for a CI_CDFT = T simulation.

COND_NUM_EXTRA_ITS  Integer  Number of iterations of preoptimisation stage during COND task 
COND_NUM_EXTRA_STATES  Integer  Number of additional conduction states optimised during the preoptimisation stage 
CONSTRAINED_DFT  Block  Manages constrainedDFT simulations. 
COULOMB_CUTOFF_LENGTH  Physical  Length of cylinder or width of slab for cutoff coulomb interaction 
COULOMB_CUTOFF_RADIUS  Physical  Radius of sphere or cylinder for cutoff coulomb interaction 
COULOMB_CUTOFF_TYPE  Text  Type of cutoff coulomb interaction: NONE, SPHERE, CYLINDER, SLAB, WIRE 
COULOMB_CUTOFF_WRITE_INT  Logical  Write realspace cutoff Coulomb interaction scalarfield 
DDEC_CONV_THRESH  Physical  Threshold for DDEC charges to be considered converged. 
DDEC_CORE_MAXIT  Integer  Maximum number of DDEC core iterations. 
DDEC_IH_FRACTION  Real  Fraction of reference ion weighting used in DDEC partitioning. 
DDEC_IH_IONIC_RANGE  Integer  Range of ionic charges for DDEC Reference densities 
DDEC_MAXIT  Integer  Maximum number of DDEC iterations. 
DDEC_MOMENT  Integer  Calculate DDEC AIM moment of order n. 
DDEC_MULTIPOLE  Logical  Calculate DDEC AIM dipoles and quadrupoles. 
DDEC_RAD_NPTS  Integer  Number of atomcentered shells used for spherical averaging and storing the DDEC AIM density profiles. 
DDEC_RAD_RCUT  Physical  Radius of the largest spherical shell for DDEC. 
DDEC_WRITE_RAD  Logical  Write AIM sphericallyaveraged density profiles. 
DENSE_THRESHOLD  Real  Threshold for matrix segments to be treated as dense 
DOS_SMEAR  Physical  Halfwidth for Gaussian smearing of density of states 
DX_FORMAT_COARSE  Logical  Makes the .dx files (see DX_FORMAT ) smaller by outputting only odd points along every axis, discarding even points.

DX_FORMAT_DIGITS  Integer  Selects the number of significant digits in .dx file (see DX_FORMAT ) output.

EDFT_COMMUTATOR_THRES  Physical  Tolerance on the total Hamiltoniandensity matrix commutator during EDFT inner loop. 
EDFT_ENERGY_THRES  Physical  Tolerance on total energy change during EDFT inner loop. 
EDFT_ENTROPY_THRES  Physical  Tolerance on total entropy change during EDFT inner loop. 
EDFT_FERMI_THRES  Physical  Tolerance on total Fermi energy change during EDFT inner loop. 
EDFT_FREE_ENERGY_THRES  Physical  Tolerance on total free energy change during EDFT inner loop. 
EDFT_RMS_GRADIENT_THRES  Real  Tolerance on the total occupancies RMS gradient during EDFT inner loop. 
ELEC_ENERGY_TOL  Physical  Tolerance on total energy change during NGWF optimisation. 
ELEC_FORCE_TOL  Physical  Tolerance on maximum force change per electronic optimisation step during NGWF optimisation 
ETRANS_CALCULATE_LEAD_MU  Logical  Calculate the lead chemical potentials via a nonself consistent band structure calculation. 
ETRANS_ECMPLX  Physical  The complex energy used to select the retarded Green's function. If set too small, instabilities may occur and the calculation of the Green's function may fail. 
ETRANS_EREF  Physical  If ETRANS_EREF_METHOD = REFERENCE, this defines the reference energy about which transmission is calculated. 
ETRANS_EREF_METHOD  Text  The method to determine the reference energy for the calculation of transmission coefficients. 
ETRANS_LEAD_NKPOINTS  Integer  The number of kpoints the lead band structure is calculated for. 
ETRANS_WRITE_HS  Logical  Write the lead and LCR Hamiltonian and Overlap matrices to disk for further analysis. 
EXACT_LNV  Logical  Use LiNunesVanderbilt algorithm (not MillamScuseria variant) 
EXTRA_N_SW  Integer  Generate extra spherical waves for NGWF representation (the extra SW will suffer of aliasing) 
FFTBOX_BATCH_SIZE  Integer  Number of NGWFs in each batch of fftboxes 
FFTBOX_PREF  Text  Preferred FFT box size 
FOE  Logical  Enable calculation of the density kernel with a Fermi Operator Expansion approach in finitetemperature DFT calculations with the EnsembleDFT method 
FOE_AVOID_INVERSIONS  Logical  Avoid performing any inversions or using any inverses in the FOE method 
FOE_CHEBY_THRES  Real  The maximum error threshold on the Chebyshev expansions in the FOE 
FOE_CHECK_ENTROPY  Logical  Validate the FOE entropy approximation against a simple quadratic form 
FOE_MU_TOL  Physical  Tolerance for stopping in FOE chemical potential search. 
FOE_TEST_SPARSITY  Logical  Test the quality of the H^2 sparsity pattern for K 
GEOM_BACKUP_ITER  Integer  Backup frequency for geometry optimisation 
GEOM_CONTINUATION  Logical  Continue a previous geometry optimisation 
GEOM_CONVERGENCE_WIN  Integer  Number of geometry optimisation iterations for convergence criteria to be met 
GEOM_DISP_TOL  Physical  Displacement convergence tolerance for geometry optimisation 
GEOM_ENERGY_TOL  Physical  Energy convergence tolerance for geometry optimisation 
GEOM_FORCE_TOL  Physical  Force convergence tolerance for geometry optimisation 
GEOM_FREQUENCY_EST  Physical  Estimated average phonon frequency for geometry optimisation 
GEOM_LBFGS_MAX_UPDATES  Integer  Maximum number of force and position updates to store when using the LBFGS method 
GEOM_MODULUS_EST  Physical  Estimated bulk modulus for geometry optimisation 
GEOM_PRECOND_EXP_A  Real  A value of the EXP preconditioner for LBFGS geometry optimisation with preconditioning 
GEOM_PRECOND_EXP_C_STAB  Physical  Stabilization constant of EXP preconditioner for LBFGS geometry optimisations 
GEOM_PRECOND_EXP_R_CUT  Physical  Cutoff distance for EXP preconditioner for LBFGS geometry optimisations 
GEOM_PRECOND_FF_C_STAB  Physical  Stabilization constant of FF preconditioner for LBFGS geometry optimisations 
GEOM_PRECOND_FF_R_CUT  Physical  Cutoff distance for FF preconditioner for LBFGS geometry optimisations 
H2DENSKERN_SPARSITY  Logical  Enable the AQuAFOE method 
HUBBARD  Block  Activate DFT+U(+J) (or LDA+U) functionality. 
ISOSURFACE_CUTOFF  Real  Determines the cutoff density alpha of the electronic density isosurface defining the volume V used in the electronic enthalpy method. 
IS_AUTO_SOLVATION  Logical  Automatically runs a calculation in vacuum before any calculation that requires implicit solvation. 
IS_BC_COARSENESS  Integer  Block size for bulk charge coarsegraining in open boundary conditions 
IS_BC_SURFACE_COARSENESS  Integer  Block size for surface charge coarsegraining in open boundary conditions 
IS_CHECK_SOLV_ENERGY_GRAD  Logical  Checks the gradient of solvation energy by finite differences 
IS_CORE_WIDTH  Physical  Implicit solvent: radius around each core where the permittivity is set to unity. 
IS_DENSITY_THRESHOLD  Real  The parameter rho_0 in the definition of the cavity (atomic units) 
IS_DIELECTRIC_FUNCTION  Text  Determines how the dielectric cavity is generated 
IS_DIELECTRIC_MODEL  Text  Determines how the dielectric cavity is generated 
IS_DISCRETIZATION_ORDER  Integer  The discretization order used for the defect correction in the multigrid calculation 
IS_MULTIGRID_DEFECT_ERROR_TOL  Real  Stop criterion for the defect correction in the multigrid calculation 
IS_MULTIGRID_ERROR_TOL  Real  Stop criterion for the multigrid calculation 
IS_PBE  Text  Chooses the equation to be solved in implicit solvation. 
IS_SC_STERIC_MAGNITUDE  Physical  Prefactor in softcore steric potential in implicit solvation with Boltzmann ions. 
IS_SEPARATE_RESTART_FILES  Logical  Uses a different set of files (.vacuum_dkn and .vacuum_tightbox_ngwfs) to construct the solute cavity for implicit solvation. 
IS_SMEARED_ION_REP  Logical  Turns on the smeared ion representation for electrostatics calculation. 
IS_SMEARED_ION_WIDTH  Physical  Characteristic width for the Gaussian smearing of ions. 
IS_SOLVATION_BETA  Real  The parameter beta in the definition of the cavity (unitless) 
IS_SOLVATION_METHOD  Text  Chooses between the direct and corrective solvation approach. 
IS_SOLVATION_OUTPUT_DETAIL  Text  Controls details of additional implicit solvent output 
KERNEL_DIIS_MAXIT  Integer  Maximum number of inner loop DIIS iterations 
KERNEL_DIIS_SCHEME  Text  Enable selfconsistent density kernel mixing or Hamiltonian mixing in the inner loop 
KERNEL_DIIS_SIZE  Integer  Maximum number of density kernels or Hamiltonians to be mixed during inner loop DIIS 
LIBXC_C_FUNC_ID  Integer  Functional ID for correlation functional in a LIBXC calculation. 
LIBXC_X_FUNC_ID  Integer  Functional ID for exchange functional in a LIBXC calculation. 
LNV_CHECK_TRIAL_STEPS  Logical  Check stability of kernel at each trial step during LNV 
LNV_THRESHOLD_ORIG  Real  Convergence threshold for density kernel RMS gradient 
LR_TDDFT_RPA  Boolean  If the flag is set to True, a full TDDFT calculation in the socalled "Random Phase Approximation" will be performed, rather than invoking the TammDancoff approximation 
MAXIT_CDFT_U_CG
 Integer  Specifies the maximum number of iterations for the constraining potentials (Uq/s) conjugate gradients optimisation. 
MAXIT_HOTELLING  Integer  Maximum number of iterations for inverting the overlap matrix 
MAXIT_LNV  Integer  Maximum number of density kernel iterations 
MAXIT_NGWF_CG  Integer  Maximum number of NGWF conjugate gradient iterations 
MAXIT_PALSER_MANO  Integer  Maximum number of PalserManolopoulos iterations 
MAXIT_PEN  Integer  Maximum number of penalty functional iterations 
MINIT_LNV  Integer  Minimum number of density kernel iterations 
NBO_SPECIES_NGWFLABEL  Block  Optional userdefined (false) lmlabel for NGWFs according to gennbo convention. 
NEB_CI_DELAY  Integer  Delay before enabling climbing image in NEB calculations. 
NEB_CONTINUATION  Boolean  Continue NEB run from .neb_cont files. 
NEB_PRINT_SUMMARY  Boolean  Print NEB summary to stdout 
NGWF_MAX_GRAD  Real  Convergence threshold for maximum NGWF gradient at any psinc grid point. 
NGWF_THRESHOLD_ORIG  Real  Convergence threshold for NGWF RMS gradient 
NUM_EIGENVALUES  Integer  Number of KohnSham states above and below Fermi level to calculate 
NUM_IMAGES  Integer  Number of ONETEP instances to run in parallel 
OPENBC_HARTREE  Logical  Switches from periodic to open boundary conditions in the calculation of Hartree energy 
OPENBC_ION_ION  Logical  Switches from periodic to open boundary conditions in the calculation of ionion energy 
OPENBC_PSPOT  Logical  Switches from periodic to open boundary conditions in the calculation of local pseudopotential energy 
PADDED_LATTICE_CART  Block  The simulation cell lattice vectors for the padded cell for Cutoff Coulomb 
PEN_PARAM  Real  Penalty functional parameter in hartree 
PRODUCT_ENERGY  Physical  Product energy in NEB calculation 
PRODUCT_ROOTNAME  Text  Product restart files' rootname in NEB calculation 
REACTANT_ENERGY  Physical  Reactant energy in NEB calculation 
REACTANT_ROOTNAME  Text  Reactant restart files' rootname in NEB calculation 
READ_HAMILTONIAN  Logical  Read the Hamiltonian matrix from a file (EDFT only) 
READ_MAX_L  Integer  Set maximum SW angular momentum (l number) when reading from file 
RUN_TIME  Real  The maximum allocated run time for this job (in seconds) 
SMOOTHING_FACTOR  Real  Smoothing factor for electronic volume step function. 
SOL_IONS  Block  Describes the kinds of Boltzmann ions in implicit solvent. 
SPECIES_ATOMIC_SET  Block  Atomic species initial NGWFs 
THERMOSTAT  Block  Molecular dynamics thermostat 
THREADS_PER_CELLFFT  Integer  Number of threads to use in OpenMPparallel FFTs on simulation cell. 
TIMINGS_LEVEL  Integer  Set level of detail in timings 
TSSEARCH_DISP_TOL  Physical  Transition state search displacement tolerance 
TSSEARCH_ENERGY_TOL  Physical  Energy convergence tolerance for transition state searching. 
TSSEARCH_FORCE_TOL  Physical  Transition state search force tolerance 
TSSEARCH_LSTQST_PROTOCOL  Text  Transition state search LSTQST protocol 
TSSEARCH_METHOD  Text  Transition state search method 
WRITE_CONVERGED_DK_NGWFS  Logical  Only write Density Kernel and NGWFs to disk upon convergence of NGWF optimisation. 
WRITE_HAMILTONIAN  Logical  Write the Hamiltonian matrix on a file (EDFT only) 
WRITE_MAX_L  Integer  Set maximum SW angular momentum (l number) when writing to file 
Keyword  Type  Description 
CDFT_CG_MAX  Real  Specifies the maximum number of constraining potential (Uq/s) conjugate gradient iterations between resets. 
CDFT_CG_MAX_STEP  Real  Maximum length of trial step for the constraining potential (Uq/s) optimisation line search. 
CDFT_CG_TYPE  Text  Specifies the variant of the conjugate gradients algorithm used for the optimization of the constraining potentials (Uq/s). 
CDFT_GURU
 Logical  Tell ONETEP you are a cDFTexpert and prevent it from initialising the active Uq/s to the failsafe value of 1 eV, overwriting the values entered in the CONSTRAINED_DFT (Uq/s) block.

CHECK_ATOMS  Logical  Check atoms are a reasonable distance apart 
COMMS_GROUP_SIZE  Integer  Size of a comms group 
COREHAM_DENSKERN_GUESS  Logical  Initialize density kernel by simple diagonalisation 
DDEC_INTERP_RAD_DENS  Logical  Trilinear postprocessing interpolation of converged DDEC AIM density 
DDEC_MIN_SHELL_DENS  Real  Minimum number of points lying in each spherical shell for DDEC. 
DDEC_REFDENS_INIT  Logical  Initialize DDEC AIM densities as neutral atom reference densities. 
DDEC_ZERO_THRESHOLD  Real  Threshold for density on grid to be excluded in order to avoid division by zero. 
DELTA_E_CONV  Logical  Use consecutive energy gains as NGWF convergence criterion 
DENSE_FOE  Logical  Use a dense matrix representation of the density kernel in the Fermi Operator Expansion approach 
EDFT_EXTRA_BANDS  Integer  Number of extra energy bands in EDFT calculations. 
EDFT_MAX_STEP  Real  Maximum step length for the linesearch update in the inner loop of EDFT calculations. 
EDFT_ROUND_EVALS  Integer  Round up the energy eigenvalues in EDFT calculations. 
EDFT_WRITE_OCC  Logical  Write occupancies in a file. 
EIGENSOLVER_ABSTOL  Real  Precision to which ScaLapack PDSYGVX eigensolver will resolve the eigenvalues. 
EIGENSOLVER_ORFAC  Real  Precision to which ScaLapack PDSYGVX eigensolver will orthonormalise the eigenvectors. 
ELEC_CG_MAX  Integer  Reset frequency for NGWF conjugate gradients 
ETRANS_LEAD_DISP_TOL  Physical  The maximum acceptable difference in the translation vectors between the atoms in a lead, and the corresponding atoms in the lead principle layer. 
ETRANS_SAME_LEADS  Logical  Use the same selfenergy for all the leads. 
EVEN_PSINC_GRID  Logical  Force even number of points in the simulationcell psinc grid. 
EXTERNAL_BC_FROM_CUBE  Logical  Read in external boundary conditions for the electrostatic potential 
GEOM_LBFGS_BLOCK_LENGTH  Integer  How many force and position updates to store before reallocation of the history vector storage in an unbounded LBFGS calculation 
GEOM_PRECOND_EXP_MU  Physical  mu value for EXP preconditioner 
GEOM_PRECOND_EXP_R_NN  Physical  Atomic nearest neighbour distance for EXP preconditioner for LBFGS geometry optimisations 
GEOM_PRINT_INV_HESSIAN  Logical  Print inverse Hessian 
GEOM_RESET_DK_NGWFS_ITER  Logical  Number of geom iterations between resets of kernel and NGWFs 
GEOM_REUSE_DK_NGWFS  Logical  Reuse density kernel and NGWFs during geometry optimisation steps 
IMAGE_SIZES  Text  Individual sizing of ONETEP images 
INITIAL_DENS_REALSPACE  Real  Construct initial density in real space from atomsolver density 
IS_APOLAR_SCALING_FACTOR  Real  Scaling factor applied to the apolar solvation term. 
IS_BC_THRESHOLD  Real  Charge density threshold for bulk charge coarsegraining in open boundary conditions 
IS_DIELECTRIC_EXCLUSIONS  Block  Describes solventexcluded regions, if any. 
IS_DIELECTRIC_EXCLUSIONS_SMEAR  Physical  Length scale that defines the extent of the smearing of dielectric exclusion region boundaries. For more details, see the implicit solvation documentation. 
IS_HC_STERIC_CUTOFF  Physical  Implicit solvent: cutoff radius for hardcore steric potential. 
IS_MULTIGRID_ERROR_DAMPING  Boolean  Turn on error damping in the multigrid defectcorrection procedure. 
IS_MULTIGRID_MAX_ITERS  Integer  Maximum number of iterations for the multigrid solver 
IS_MULTIGRID_NLEVELS  Integer  Number of multigrid levels for the multigrid solver 
IS_MULTIGRID_VERBOSE  Boolean  Output crosssections of quantities that are of interest during multigrid calculations to text files. 
IS_MULTIGRID_VERBOSE_Y  Physical  Specifies the offset along the Y axis for crosssections performed with IS_MULTIGRID_VERBOSE . 
IS_MULTIGRID_VERBOSE_Z  Physical  Specifies the offset along the Z axis for crosssections performed with IS_MULTIGRID_VERBOSE . 
IS_PBE_BC_DEBYE_SCREENING  Boolean  Specifies whether boundary conditions in implicit solvation with Boltzmann terms should use Debye screening (lambda*exp) factor. 
IS_PBE_EXP_CAP  Double  Sets a numerical cap at the arguments in the exp() in PoissonBoltzmann terms in implicit solvation. 
IS_PBE_TEMPERATURE  Double  Sets the temperature for the Boltzmann term in implicit solvation. 
IS_PBE_USE_FAS  Boolean  Specifies whether the full aproximation scheme (FAS) should be used for the solution of the PoissonBoltzmann equation in implicit solvation. 
IS_SC_STERIC_CUTOFF  Physical  Cutoff radius for softcore steric potential in implicit solvation with Boltzmann ions. 
IS_SC_STERIC_SMOOTHING_ALPHA
 Physical  Smoothing factor alpha in softcore steric potential in implicit solvation with Boltzmann ions. 
IS_STERIC_WRITE  Boolean  Specifies whether the steric potential (used in implicit solvation with Boltzmann ions) is to be written to a (dx/cube/grd) file. 
IS_SURFACE_THICKNESS  Real  Surface film thickness (in atomic units of charge density) used for the determination of cavity surface area 
KERNEL_DIIS_COEFF  Real  Fraction of the output density kernel or Hamiltonian matrix for linearmixing inner loop DIIS 
KERNEL_DIIS_CONV_CRITERIA  Text  Convergence criteria for inner loop DIIS 
KERNEL_DIIS_LINEAR_ITER  Integer  Number of linearmixing iterations preceeding Pulay or LiST mixing in the inner loop DIIS method 
KERNEL_DIIS_LSHIFT  Physical  Levelshifting energy during inner loop DIIS. 
KERNEL_DIIS_LS_ITER  Integer  Number of inner loop DIIS iterations with levelshifting enabled. 
KERNEL_DIIS_THRESHOLD  Real  Convergence threshold for inner loop DIIS 
KERNEL_UPDATE  Logical  Update density kernel during NGWF line search 
K_ZERO  Physical  Parameter for kinetic energy preconditioning. 
LNV_CG_MAX_STEP  Real  Maximum length of trial step for kernel optimisation line search 
LNV_CG_TYPE  Text  Variant of conjugate gradient algorithm to use for density kernel optimisation 
LOCPOT_SCHEME  Text  Scheme for symmetrising local potential matrix 
LR_TDDFT_ANALYSIS  Logical  If the flag is set to True, a full cubicscaling analysis of each TDDFT excitation is performed in which the response density is decomposed into dominant KohnSham transitions. 
LR_TDDFT_CG_THRESHOLD  Real  The keyword specifies the convergence tolerance on the sum of the n TDDFT excitation energies. 
LR_TDDFT_JOINT_SET  Logical  If the flag is set to T, the joint NGWF set is used to represent the conduction space in the LRTDDFT calculation. 
LR_TDDFT_KERNEL_CUTOFF  Physical  Keyword sets a truncation radius on all response density kernels in order to achieve linear scaling computational effort with system size. 
LR_TDDFT_MAXIG_CG  Integer  The maximum number of conjugate gradient iterations the algorithm will perform. 
LR_TDDFT_MAXIT_PEN  Integer  The maximum number purification iterations performed per conjugate gradient step. 
LR_TDDFT_NUM_STATES  Integer  The keyword specifies how many excitations we want to converge. 
LR_TDDFT_PENALTY_TOL  Real  Keyword sets a tolerance for the penalty functional. 
LR_TDDFT_PROJECTOR  Logical  If the flag is set to True, the conduction density matrix is redefined to be a projector onto the entire unoccupied subspace. 
LR_TDDFT_RESTART  Logical  If the flag is set to True, the algorithm reads in LR_TDDFT_NUM_STATES response density kernels in .dkn format and uses them as initial trial vectors for a restarted LRTDDFT calculation. 
LR_TDDFT_TRIPLET  Logical  Flag that decides whether the LR_TDDFT_NUM_STATES states to be converged are singlet or triplet states. 
LR_TDDFT_WRITE_DENSITIES
 Logical  If the flag is set to True, the response density, electron density and hole density for each excitation is computed and written into a .cube file. 
LR_TDDFT_WRITE_KERNELS
 Logical  If the flag is set to T, the TDDFT response density kernels are printed out at every conjugate gradient iteration. These files are necessary to restart a LRTDDFT calculation. 
MAX_RESID_HOTELLING  Real  Maximum residual value allowed when inverting overlap matrix 
MG_DEFCO_FD_ORDER  Integer  Order of finite differences to use in the highorder defect correction component of the multigrid solver. 
MG_GRANULARITY_POWER  Integer  Power of 2 which gives multigrid granularity. 
MG_TOL_RES_REL  Real  Relative tolerance in norm of residual for defect correction procedure in multigrid solver. 
MIX_DKN_INIT_NUM  Integer  Length of the initialization phase for the density kernel. 
MIX_DKN_INIT_TYPE  Text  Specifies the mixing scheme used during the initialisation phase for the density kernel. 
MIX_DKN_NUM  Integer  Number of independent coefficients used to build new guesses for the density kernel. 
MIX_DKN_RESET  Integer  Every N MD steps, the density kernel mixing/extrapolation scheme is reset and a new initial guess for the density kernel is built according to COREHAM_DENSKERN_GUESS . 
MIX_DKN_TYPE  Text  Type of mixing used to build new guesses for the density kernel 
MIX_LOCAL_LENGTH  Physical  Characteristic length of the mixing scheme 
MIX_LOCAL_SMEAR  Physical  Smearing length of the mixing scheme 
MIX_NGWFS_INIT_NUM  Integer  Length of the initialization phase for the NGWFs. 
MIX_NGWFS_INIT_TYPE  Text  Specifies the mixing scheme used during the initialisation phase for the NGWFs. 
MIX_NGWFS_NUM  Integer  Number of independent coefficients used to build new guesses for the NGWFs 
MIX_NGWFS_RESET  Integer  Every N MD steps, the NGWFs mixing/extrapolation scheme is reset and a new initial guess for the NGWFs is built according to SPECIES_ATOMIC_SET . 
MIX_NGWFS_TYPE  Text  Type of mixing used to build new guesses for the NGWFs. 
NBO_AOPNAO_SCHEME  Text  The AO to PNAO scheme to use. 
NBO_INIT_LCLOWDIN  Logical  Performs atomlocal Lowdin orthogonalisation on NGWFs as the first step before constructing NAOs. 
NBO_PNAO_ANALYSIS  Logical  Perform s/p/d/f analysis on the PNAOs (analogous to NGWF_ANALYSIS ).

NBO_SCALE_DM  Logical  Scales partial density matrix output to seedname_nao_nbo.47 in order to achieve charge integrality. 
NBO_SCALE_SPIN  Logical  Scales alpha and beta spins independently to integral charge when partial matrices are printed and NBO_SCALE_DM = T. 
NBO_WRITE_LCLOWDIN  Logical  Writes full matrices (all atoms) in the atomlocal Lowdinorthogonalized basis to FILE.47 
NGWF_CG_MAX_STEP  Real  Maximum length of trial step for NGWF optimisation line search. 
NGWF_CG_ROTATE  Logical  Rotate density kernel to the new NGWF representation after CG update. In EDFT calculations, it also rotates the eigenvectors. 
NGWF_CG_TYPE  Text  Variant of conjugate gradient algorithm to use for NGWF optimisation 
NGWF_HALO  Real  Halo width for NGWF radii in bohr 
NONSC_FORCES  Logical  Calculate residual non selfconsistent forces 
OCC_MIX  Real  Mixing fraction of occupancy preconditioned NGWF gradient 
ODD_PSINC_GRID  Logical  Force and odd number of points in the simulation cell psinc grid 
OLD_LNV  Logical  Use legacy algorithm for backwards compatibility 
OPENBC_PSPOT_FINETUNE_ALPHA  Real  Controls the alpha parameter used in the calculation of openBC local pseudopotential 
OPENBC_PSPOT_FINETUNE_F  Integer  Controls the f parameter used in the calculation of openBC local pseudopotential 
OPENBC_PSPOT_FINETUNE_NPTSX  Integer  Controls the npts_x parameter used in the calculation of openBC local pseudopotential 
OVLP_FOR_NONLOCAL  Logical  Use overlap sparsity pattern for nonlocal pseudopotential matrix 
PBC_CORRECTION_CUTOFF  Physical  Turn on MartynaTuckerman correction to the effects of periodic boundary conditions, with a specified dimensionless cutoff. 
POLARISATION_SIMCELL_CALCULATE  Boolean  Perform calculation of polarisation in a properties calculation. 
PPD_NPOINTS  Text  PPD size in grid points 
PRECOND_REAL  Logical  Apply kinetic energy preconditioning in real space 
PRECOND_RECIP  Logical  Apply kinetic energy preconditioning in reciprocal space 
PRECOND_SCHEME  Text  Specify scheme for kinetic energy preconditioning 
PRINT_QC  Logical  Print calculation summary for quality control testing 
PROJECTORS_PRECALCULATE  Logical  Whether to preevaluate projectors in FFTboxes 
PSINC_SPACING  Text  Psinc grid spacing in bohr 
R_PRECOND  Physical  Radial cutoff for realspace preconditioning 
SMOOTH_PROJECTORS  Real  Halfwidth of Gaussian filter for smoothing nonlocal projectors in bohr 
THREADS_PER_FFTBOX  Integer  Number of nested threads used for FFT box operations. 
TSSEARCH_CG_MAX_ITER  Integer  Maximum number of transition state search conjugate gradients iterations 
TSSEARCH_QST_MAX_ITER  Integer  Maximum number of transition state search QST iterations 
TURN_OFF_EWALD  Boolean  Elides the calculation of Ewald energy and force terms in the calculation. 
USE_SPACE_FILLING_CURVE  Logical  Distribute atoms according to a spacefilling curve 
USE_SPH_HARM_ROT  Boolean  Manually activate the sph_harm_rotation (spherical harmonic rotation) module.

VDW_DCOEFF  Real  Overrides the damping constant associated with a damping function. 
VDW_PARAMS  Block  Override the default parameters of the dispersion damping functions. 
ZERO_TOTAL_FORCE  Logical  Subtract average ionic force from all forces to make the total ionic force zero 
Syntax:  BSUNFLD_KPOINT_PATH [Block]  
Syntax: 
 
Description:  Kpoint path for bandstructure unfolding calculation.
 
Default Value:  
Example: 
 
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Syntax:  BSUNFLD_TRANSFORMATION [Block]  
Syntax: 
 
Description:  Transformation matrix (flattened) between primitivecell and supercell lattice vectors when unfolding bandstructure  
Default Value:  
Example: 
 
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Syntax:  BS_KPOINT_PATH [Block]  
Syntax: 
 
Description:  Kpoint path for bandstructure calculation.
 
Default Value:  
Example: 
 
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Syntax:  BS_KPOINT_PATH_SPACING [Physical]
 
Description:  Kpoint spacing along the bandstructure path.  
Default Value: 
 
Example: 
bs_kpoint_path_spacing 0.004 "1/bohr"  
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Syntax:  BS_METHOD [Integer]
 
Description:  The method to use for the calculation of band structures  either the tightbinding style method or the k.p perturbation theory style method.  
Default Value: 
 
Example: 
bs_method kp  
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Syntax:  BS_NUM_EIGENVALUES [Integer]  
Description:  Number of energy and occupancy eigenvalues to print below and above the Fermi level from a bandstructure calculation. If left as default all eigenvalues (2 x number of occupied states) will be printed.
 
Default Value: 
 
Example: 
bs_num_eigenvalues 10  
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Syntax:  CDFT_ATOM_CHARGE [Logical]  
Description:  Activate atom chargeconstrainedDFT mode. This mode is incompatible with any other cDFTmode.
 
Default Value: 
 
Example: 
cdft_atom_charge T  
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Syntax:  CDFT_ATOM_SPIN [Logical]  
Description:  Activate atom magneticmomentconstrainedDFT mode. This mode is incompatible with any other cDFTmode.
 
Default Value: 
 
Example: 
cdft_atom_spin T  
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Syntax:  CDFT_CG_MAX [Real]  
Description:  Specifies the maximum number of constraining potential (Uq/s) conjugate gradient iterations between resets.  
Default Value: 
 
Example: 
cdft_cg_max 1  
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Syntax:  CDFT_CG_MAX_STEP [Real]  
Description:  Maximum length of trial step for the constraining potential (Uq/s) optimisation line search.  
Default Value: 
 
Example: 
cdft_cg_max_step 10.0  
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Syntax:  CDFT_CG_THRESHOLD [Real]  
Description:  Specifies the convergence threshold for the RMS gradient of the constraining potentials (Uq/s).  
Default Value: 
 
Example: 
cdft_cg_threshold 0.01  
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Syntax:  CDFT_CG_TYPE [Text]  
Description:  Specifies the variant of the conjugate gradients algorithm used for the optimization of the constraining potentials (Uq/s), currently either NGWF_FLETCHER for FletcherReeves or NGWF_POLAK for PolakRibiere.
 
Default Value: 
 
Example: 
cdft_cg_type NGWF_POLAK  
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Syntax:  CDFT_CHARGE_ACCEPTOR_TARGET [Real]  
Description:  Targeted acceptorgroup electron population for acceptorgroup chargeconstrainedDFT mode [CDFT_GROUP_CHARGE_ACCEPTOR = T].
 
Default Value: 
 
Example: 
cdft_charge_acceptor_target 17  
Example:  ; Constrain Nup+Ndown=17 e in subspace.  
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Syntax:  CDFT_CHARGE_DONOR_TARGET [Real]  
Description:  Targeted donorgroup electron population for donorgroup chargeconstrainedDFT mode [CDFT_GROUP_CHARGE_DONOR = T]  
Default Value: 
 
Example: 
cdft_charge_donor_target 17  
Example:  ; Constrain Nup+Ndown=17 e in subspace.  
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Syntax:  CDFT_CONTINUATION [Logical]  
Description:  Continue a constraining potential (Uq/s) optimisation from a previous run using the .cdft file with the latest cDFTpotentials. CDFT_CONTINUATION = T allows also to perform singlepoint cDFT runs (MAXIT_CDFT_U_CG = 0) reading atomspecific constraining potentials from .cdft file (instead of speciesspecific ones from the CONSTRAINED_DFT block). For CDFT_CONTINUATION = T, the constraining potentials (Uq/s) are read from the .cdft file no matter the setting of CDFT_GURU .
 
Default Value: 
 
Example: 
cdft_continuation T  
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Syntax:  CDFT_ELEC_ENERGY_TOL [Value] [Unit]  
Description:  Tolerance on energy change per atom during CDFT optimisation. If negative, the option is deactivated.  
Default Value: 
 
Example: 
cdft_elec_energy_tol 0.01 hartree  
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Syntax:  CDFT_GROUP_CHARGE_ACCEPTOR [Logical]  
Description:  Activate acceptorgroup chargeconstrainedDFT mode. This mode is compatible with CDFT_GROUP_CHARGE_DONOR and CDFT_GROUP_SPIN_ACCEPTOR /CDFT_GROUP_SPIN_DONOR cDFTmodes, and incompatible with CDFT_ATOM_CHARGE /CDFT_ATOM_SPIN and CDFT_GROUP_CHARGE_DIFF /CDFT_GROUP_SPIN_DIFF modes.
 
Default Value: 
 
Example: 
cdft_group_charge_acceptor T  
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Syntax:  CDFT_GROUP_CHARGE_DIFF [Logical]  
Description:  Activate group chargedifference constrainedDFT mode. This mode is compatible with CDFT_GROUP_SPIN_DIFF cDFT mode only. Thus, it is incompatible with any other CDFT_ATOM_CHARGE/SPIN and CDFT_GROUP_CHARGE/SPIN_ACCEPTOR/DONOR cDFT modes.
 
Default Value: 
 
Example: 
cdft_group_charge_diff T  
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Syntax:  CDFT_GROUP_CHARGE_DIFF_TARGET [Real]  
Description:  Targeted electron population difference between acceptor and donor group for groupchargedifference constrainedDFT mode [CDFT_GROUP_CHARGE_DIFF =T].  
Default Value: 
 
Example: 
cdft_group_charge_diff_target 2  
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Syntax:  CDFT_GROUP_CHARGE_DONOR [Logical]  
Description:  Activate donorgroup chargeconstrainedDFT mode. This mode is compatible with CDFT_GROUP_CHARGE_ACCEPTOR and CDFT_GROUP_SPIN_ACCEPTOR /CDFT_GROUP_SPIN_DONOR cDFTmodes, and incompatible with CDFT_ATOM_CHARGE /CDFT_ATOM_SPIN and CDFT_GROUP_CHARGE_DIFF /CDFT_GROUP_SPIN_DIFF modes.  
Default Value: 
 
Example: 
cdft_group_charge_donor T  
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Syntax:  CDFT_GROUP_CHARGE_DOWN_ONLY [Logical]  
Description:  Constrain only SPINDOWN channel in CDFT_GROUP_CHARGE_ACCEPTOR , CDFT_GROUP_CHARGE_DONOR and CDFT_GROUP_CHARGE_DIFF modes. To avoid disaster, make sure the specified CDFT_CHARGE_ACCEPTOR/DONOR_TARGET or CDFT_CHARGE_DIFF_TARGET keywords are consistent with the fact only one spin channel is being constrained. This functionality is NOT compatible with CDFT_GROUP_CHARGE_UP_ONLY, CDFT_ATOM_CHARGE/SPIN, and CDFT_GROUP_SPIN_ACCEPTOR/DONOR and CDFT_GROUP_SPIN_DIFF cDFT modes.  
Default Value: 
 
Example: 
cdft_group_charge_down_only T  
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Syntax:  CDFT_GROUP_CHARGE_UP_ONLY [Logical]  
Description:  Constrain only SPINUP channel in CDFT_GROUP_CHARGE_ACCEPTOR , CDFT_GROUP_CHARGE_DONOR and CDFT_GROUP_CHARGE_DIFF modes. To avoid disaster, make sure the specified CDFT_CHARGE_ACCEPTOR/DONOR_TARGET or CDFT_CHARGE_DIFF_TARGET keywords are consistent with the fact only one spin channel is being constrained. This functionality is NOT compatible with CDFT_GROUP_CHARGE_UP_ONLY, CDFT_ATOM_CHARGE/SPIN, and CDFT_GROUP_SPIN_ACCEPTOR/DONOR and CDFT_GROUP_SPIN_DIFF cDFT modes.  
Default Value: 
 
Example: 
cdft_group_charge_up_only T  
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Syntax:  CDFT_GROUP_SPIN_ACCEPTOR [Logical]  
Description:  Activate acceptorgroup magneticmomentconstrainedDFT mode. This mode is compatible with CDFT_GROUP_SPIN_DONOR and CDFT_GROUP_CHARGE_ACCEPTOR /CDFT_GROUP_CHARGE_DONOR cDFTmodes, and incompatible with CDFT_ATOM_CHARGE /CDFT_ATOM_SPIN and CDFT_GROUP_CHARGE_DIFF /CDFT_GROUP_SPIN_DIFF modes.  
Default Value: 
 
Example: 
cdft_group_spin_acceptor T  
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Syntax:  CDFT_GROUP_SPIN_DIFF [Logical]  
Description:  Activate group magneticmomentdifference constrainedDFT mode. This mode is compatible with CDFT_GROUP_CHARGE_DIFF cDFT mode only. Thus, it is incompatible with any other CDFT_ATOM_CHARGE/SPIN and CDFT_GROUP_CHARGE/SPIN_ACCEPTOR/DONOR cDFT modes.  
Default Value: 
 
Example: 
cdft_group_spin_diff T  
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Syntax:  CDFT_GROUP_SPIN_DIFF_TARGET [Real]  
Description:  Targeted magneticmoment difference between acceptor and donor group for groupmagneticmomentdifference constrainedDFT mode [CDFT_GROUP_SPIN_DIFF =T].  
Default Value: 
 
Example: 
cdft_group_spin_diff_target 2  
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Syntax:  CDFT_GROUP_SPIN_DONOR [Logical]  
Description:  Activate donorgroup magneticmomentconstrainedDFT mode. This mode is compatible with CDFT_GROUP_SPIN_ACCEPTOR and CDFT_GROUP_CHARGE_ACCEPTOR /CDFT_GROUP_CHARGE_DONOR cDFTmodes, and incompatible with CDFT_ATOM_CHARGE /CDFT_ATOM_SPIN and CDFT_GROUP_CHARGE_DIFF /CDFT_GROUP_SPIN_DIFF modes.  
Default Value: 
 
Example: 
cdft_group_spin_donor T  
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Syntax:  CDFT_GURU [Logical]  
Description:  Tell ONETEP you are a cDFTexpert and prevent it from initialising the active Uq/s to the failsafe value of 1 eV, overwriting the values entered in the CONSTRAINED_DFT (Uq/s) block.
 
Default Value: 
 
Example: 
cdft_guru T  
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Syntax:  CDFT_HUBBARD [Logical]  
Description:  Activate the constrainedDFT+U functionality. It requires specifications of a positive value for the Hubbard correction (Uh) in the CONSTRAINED_DFT Block.  
Default Value: 
 
Example: 
cdft_hubbard T  
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Syntax:  CDFT_MAX_GRAD [Real]  
Description:  Specifies the convergence threshold for the maximum value of the constrainingpotential (Uq/s) gradient at any cDFTsite.  
Default Value: 
 
Example: 
cdft_max_grad 0.01  
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Syntax:  CDFT_MULTI_PROJ [Logical]  
Description:  Activate the “as many cDFTprojectors as NGWFs” cDFTmode. In this mode, the number of cDFTprojectors for a given cDFTatom equals the number of NWGFs for that atom as specified in the SPECIES block. Both the cDFTprojectors and the NGWFs are localised within spheres of the same radius. When activated, this mode overwrites the Lprojectors and Zprojectors settings in the CONSTRAINED_DFT block, and the cDFTprojectors are built according to the settings in the SPECIES_ATOMIC_SET block for that atom=cDFTsite.  
Default Value: 
 
Example: 
cdft_multi_proj T  
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Syntax:  CDFT_PRINT_ALL_OCC [Logical]  
Description:  Print detailed information of occupancies for al the cDFTsites, for OUTPUT_DETAIL = VERBOSE.
 
Default Value: 
 
Example: 
cdft_print_all_occ T  
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Syntax:  CDFT_READ_PROJ [Logical]  
Description:  Read cDFTprojectors from .tightbox_hub_proj file. Activation of this keyword overwrites any Zprojector setting in the CONSTRAINED_DFT block. It also makes not necessary to set HUBBARD_PROJ_MIXING < 0 to have task=HUBBARDSCF run with fileread projectors.
 
Default Value: 
 
Example: 
cdft_read_proj T  
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Syntax:  CDFT_SPIN_ACCEPTOR_TARGET [Real]  
Description:  Targeted group magneticmoment for acceptorgroup magneticmoment constrainedDFT mode [CDFT_GROUP_SPIN_ACCEPTOR = T].  
Default Value: 
 
Example: 
cdft_spin_acceptor_target 2  
Example:  ; Constrain NupNdown=2 e in subspace.  
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Syntax:  CDFT_SPIN_DONOR_TARGET [Real]  
Description:  Targeted group magneticmoment for donorgroup magneticmoment constrainedDFT mode [CDFT_GROUP_SPIN_DONOR = T].  
Default Value: 
 
Example: 
cdft_spin_donor_target 2  
Example:  ; Constrain NupNdown=2 e in subspace.  
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Syntax:  CDFT_TRIAL_LENGTH [Real]  
Description:  Specifies initial trial length for first step of constrainingpotential (Uq/s) conjugate gradients optimisation.
 
Default Value: 
 
Example: 
cdft_trial_length 1.0  
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Syntax:  CHARGE [Integer]
 
Description:  Specifies the total charge of the system in units of the proton charge i.e. a positive charge corresponds to a system deficient of electrons.  
Default Value: 
 
Example: 
charge +1  
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Syntax:  CHECK_ATOMS [Logical]
 
Description:  Perform a check on the atomic positions to ensure that no two atoms are unphysically close.  
Default Value: 
 
Example: 
check_atoms F  
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Syntax:  CI_CDFT [Logical]  
Description:  Perform a Configuration Interaction calculation based on constrainedDFT configurations.  
Default Value: 
 
Example: 
ci_cdft T  
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Syntax:  CI_CDFT_NUM_CONF [Integer]  
Description:  Specifies the number of constrainedDFT configuration available for a CI_CDFT = T simulation.
 
Default Value: 
 
Example: 
ci_cdft_num_conf 4  
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Syntax:  CLASSICAL_INFO [Block]
 
Syntax: 
 
Description:  Introduce classical point charges in the system (no NGWFs are associated to them). The classical point charges interact via classical Coulomb interactions with the atoms and the rest of point charges. Specifies the atomic positions as Cartesian coordinates in atomic units (a0). In the above syntax, Si denotes the species of the charge (max 4 characters),Ri its position vector and Chi the charge in atomic units.  
Default Value:  
Example: 
 
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Syntax:  COMMS_GROUP_SIZE [Text]  
Description:  To reduce comms bandwidth in an MPI job, groups of MPI processes are specified which preshare matrix and cellgrid data between themselves before communicationsheavy routines, such as sparse matrix algebra and cell extract/deposit routines. This integer specifies the size of these groups. This might often be most advantageously be set to the size of a physical "node" of a the parallel computer (ie the number of processes which share each chunk of physical memory).
 
Default Value: 
 
Example: 
comms_group_size 16  
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Syntax:  COND_CALC_MAX_EIGEN [Logical]  
Description:  Calculate maximum conduction Hamiltonian eigenvalue at the start of each NGWF CG optimisation step, for use in updating the shift for the projected conduction Hamiltonian.
 
Default Value: 
 
Example: 
cond_calc_max_eigen  
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Syntax:  COND_CALC_OPTICAL_SPECTRA [Logical]
 
Description:  Calculate the optical matrix elements in the momentum representation, required for extended systems and molecules with large NGWF radii. If false the position representation is instead used.  
Default Value: 
 
Example: 
cond_calc_optical_spectra T  
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Syntax:  COND_ENERGY_GAP [Physical]  
Description:  Energy gap required above states that will be optimised during a conduction NGWF optimisation. The number of states may be increased until such a gap is found.  
Default Value: 
 
Example: 
cond_energy_gap 0.1 eV  
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Syntax:  COND_ENERGY_RANGE [Physical]  
Description:  Energy range of states that will be optimised during a conduction NGWF optimisation. This is counted as the number of states measured from the highest occupied molecular orbital (HOMO).
Negative values mean this range is not used in determining the occupancy of the conduction kernel.  
Default Value: 
 
Example: 
cond_energy_range 5.0 eV  
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Description:  Keep shift for projected conduction Hamiltonian constant in COND task 
Default Value:  
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Syntax:  COND_INIT_SHIFT [Physical]  
Description:  Initial shifting factor for projected conduction Hamiltonian, added to each eigenvalue.
 
Default Value: 
 
Example: 
cond_init_shift 0.1 "hartree"  
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Syntax:  COND_KERNEL_CUTOFF [Physical]  
Description:  Specifies the conduction density kernel spatial cutoff in atomic units (a0). Matrix elements are only included if the corresponding conduction NGWF centres are closer than this distance.
 
Default Value: 
 
Example: 
cond_kernel_cutoff 25.0 "bohr"  
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Syntax:  COND_MAXIT_LNV [Integer]  
Description:  Max number of LNV iterations during conduction NGWF optimisation.  
Default Value: 
 
Example:  cond_maxit_lnv 20  
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Syntax:  COND_MINIT_LNV [Integer]  
Description:  Minimum number of LNV iterations during conduction NGWF optimisation.  
Default Value: 
 
Example:  cond_minit_lnv 15  
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Syntax:  COND_NUM_EXTRA_ITS [Integer]
 
Description:  The number of iterations for which the conduction NGWFs are optimised for COND_NUM_STATES + COND_NUM_EXTRA_STATES during an initial preoptimisation stage to help avoid becoming trapped in local minima. If COND_NUM_EXTRA_STATES = 0 this is ignored.  
Default Value: 
 
Example: 
cond_num_extra_its 5  
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Syntax:  COND_NUM_EXTRA_STATES [Integer]  
Description:  The number of additional conduction states to be optimised during an initial preoptimisation stage to help avoid becoming trapped in local minima. This follows the same guidelines as COND_NUM_STATES . See also COND_NUM_EXTRA_ITS .
 
Default Value: 
 
Example: 
cond_num_extra_states 10  
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Syntax:  COND_NUM_STATES [Integer]
 
Description:  The number of conduction states to be optimised (spin up + down). For nonspinpolarised calculations, this should be an even number.  
Default Value: 
 
Example: 
cond_num_states 20  
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Syntax:  COND_PLOT_JOINT_ORBITALS [Logical]  
Description:  Plot orbitals in the joint valenceconduction NGWF basis following a conduction calculation. Applies to HOMO_PLOT and LUMO_PLOT . See also COND_PLOT_VC_ORBITALS .
 
Default Value: 
 
Example: 
cond_plot_joint_orbitals F  
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Description:  Plot orbitals in separate val cond bases following COND task 
Default Value:  
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Syntax:  COND_READ_DENSKERN [Logical]  
Description:  Read in the conduction density kernel from disk. If the input filename is rootname.dat then the conduction density kernel filename is rootname.dkn_cond .
 
Default Value: 
 
Example: 
cond_read_denskern T  
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Syntax:  COND_READ_TIGHTBOX_NGWFS [Logical]  
Description:  Read in the conduction NGWFs from disk. If the input filename is rootname.dat then the conduction NGWFs filename is rootname.tightbox_ngwfs_cond .
 
Default Value: 
 
Example: 
cond_read_tightbox_ngwfs T  
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Syntax:  COND_SHIFT_BUFFER [Physical]  
Description:  Additional buffer to add to the highest calculated eigenvalue when updating the shift for the projected conduction Hamiltonian.
 
Default Value: 
 
Example: 
cond_shift_buffer 0.5 "hartree"  
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Syntax:  COND_SPEC_CALC_MOM_MAT_ELS [Logical]
 
Description:  Calculate the optical matrix elements in the momentum representation, required for extended systems and molecules with large NGWF radii. If false the position representation is instead used.  
Default Value: 
 
Example: 
cond_spec_calc_mom_mat_els F  
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Syntax:  COND_SPEC_CALC_NONLOC_COMM [Logical]  
Description:  Calculate the commutator between the nonlocal potential and the position operator, required for accurate calculation of optical absorption spectra when COND_SPEC_CALC_MOM_MAT_ELS = true.
 
Default Value: 
 
Example: 
cond_spec_calc_nonloc_comm F  
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Syntax:  COND_SPEC_CONT_DERIV [Logical]  
Description:  Calculate the commutator between the nonlocal potential and the position operator (when COND_SPEC_CALC_NONLOC_COMM : true ) using a continuous derivative in kspace. If false a finite difference is instead used in kspace.
 
Default Value: 
 
Example: 
cond_spec_cont_deriv F  
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Syntax:  COND_SPEC_NONLOC_COMM_SHIFT [Real]  
Description:  Finite difference shift used for calculating the commutator between the nonlocal potential and the position operator if calculating using finite differences (i.e. when COND_SPEC_CONT_DERIV : false ).
 
Default Value: 
 
Example: 
cond_spec_nonloc_comm_shift 0.00001  
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Syntax:  CONSTANT_EFIELD [Text]
 
Description:  Specifies a constant electric field to apply to the system in terms of Cartesian vector components in atomic units Ha/(e a0).  
Default Value: 
 
Example: 
constant_efield 1.0e3 0.0 0.0  
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Syntax: 
 
Description:  Manages constrainedDFT simulations. Provided CDFT_MULTI_PROJ = F, for species S and subspace of angular momentum channel L (with principal quantum number n=L+1) we apply charge spinspecific [Uq(UP), Uq(DOWN)] or magneticmomentspecific (Us) constraining potentials (in eV). For CDFT_ATOM_CHARGE = T, N(UP) and N(DOWN) indicate the targeted epopulation for spinchannel UP and DOWN, respectively. For CDFT_ATOM_SPIN = T, [N1(UP)N1(DOWN)] indicates the targeted epopulation difference (i.e. local magnetic moment). Uh indicates the optional Hubbard parameter (U, eV) to be
applied for CDFT_HUBBARD = T. An effective nuclear charge Z defines the hydrogenic orbitals spanning the subspace unless a negative value is given, e.g., Z=10, in which case the NGWFs initial guess orbitals (numerical atomic orbitals) are used. Depending on the activated cDFTmode, different columns of the block are used. These are:
CDFT_ATOM_CHARGE = T
CDFT_ATOM_SPIN = T
CDFT_GROUP_CHARGE_ACCEPTOR = T, CDFT_GROUP_CHARGE_DONOR = T, or CDFT_GROUP_CHARGE_DIFF = T. In this case, Uq(UP) must be equal to Uq(DOWN). Acceptor and donor atoms are differentiated by mean of negative [Uq(UP/DOWN)<0] and positive [Uq(UP/DOWN)>0] constrainingpotentials, respectively. Setting Uq=0 will result in the given cDFTatom being excluded from the list of the atoms in a given CDFT_GROUP_CHARGE_DONOR/ACCEPTOR/DIFF group.
CDFT_GROUP_SPIN_ACCEPTOR = T, CDFT_GROUP_SPIN_DONOR = T, or CDFT_GROUP_SPIN_DIFF = T. In this case, Acceptor and donor atoms are differentiated by mean of negative (Us<0) and positive (Us>0) constrainingpotentials, respectively. Setting Us=0 will result in the given cDFTatom being excluded from the list of the atoms in a given CDFT_GROUP_SPIN_DONOR/ACCEPTOR/DIFF group.
 
Default Value:  
Example: 
 
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Syntax:  COREHAM_DENSKERN_GUESS [Logical]
 
Description:  Generate an initial guess for the density kernel using a Hamiltonian generated by simple atomic screening of the pseudopotential. The density kernel may be obtained by the PalserManolopoulos algorithm or direct diagonalization. If false, a simple diagonal approximation is used for the density kernel.  
Default Value: 
 
Example: 
coreham_denskern_guess F  
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Syntax:  COULOMB_CUTOFF_LENGTH [Value] [Unit]  
Description:  Cutoff Coulomb only. Chooses the length of either (a) the cylinder on which the Coulomb interaction is truncated, in the case of a cylindrical cutoff, or (b) the slab on which the Coulomb interaction is truncated, in the case of a slab cutoff.
 
Default Value: 
 
Example: 
coulomb_cutoff_length 100 bohr  
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Syntax:  COULOMB_CUTOFF_RADIUS [Value] [Unit]  
Description:  Cutoff Coulomb only. Chooses the radius of the sphere, cylinder or wire on which the Coulomb interaction is truncated.
 
Default Value: 
 
Example: 
coulomb_cutoff_radius 100 bohr  
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Syntax:  COULOMB_CUTOFF_TYPE [Text]  
Description:  Activates Cutoff Coulomb interactions, and chooses which type of cutoff to apply. Allowed values are: NONE, SPHERE, CYLINDER, SLAB, WIRE.
 
Default Value: 
 
Example: 
coulomb_cutoff_type SPHERE  
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Syntax:  COULOMB_CUTOFF_WRITE_INT [Value]
 
Description:  Writes a scalarfield plot of the Cutoff Coulomb interaction for the chosen geometry and cutoff type. Plots .grd or .cube according to the options chosen for GRD_FORMAT and CUBE_FORMAT  
Default Value: 
 
Example: 
coulomb_cutoff_write_int T  
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Syntax:  CUBE_FORMAT [Logical]  
Description:  Output volumetric data (e.g. charge density, potential, NGWFs, canonical orbitals) in cube format . This can be visualized using free software such as gOpenMol , MOLEKEL and XCrySDen .
 
Default Value: 
 
Example: 
cube_format T  
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Syntax:  CUTOFF_ENERGY [Value] [Unit]
 
Description:  Chooses the psinc basis set to correspond as closely as possible to a planewave basis with this cutoff energy. See section 3 of Skylariset al.,J. Phys.: Condens. Matter17, 5757 (2005) for more details.  
Default Value: 
 
Example: 
cutoff_energy 500 eV  
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Syntax:  DBL_GRID_SCALE [Real]  
Description:  Ratio of charge density / potential working grid to standard grid (1 or 2 only).  
Default Value: 
 
Example:  dbl_grid_scale 1.0  
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Syntax:  ddec_calculate [Logical]  
Description:  Activate Density Derived Electrostatic and Chemical analysis routines.  
Default Value: 
 
Example: 
ddec_calculate T  
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Syntax:  ddec_classical_hirshfeld [Logical]  
Description:  Output results from classical Hirshfeld partitioning, which are the atomic charges from the 1st iteration of DDEC. Reference densities must be initialised as neutral atomic densities using the keyword 'ddec_refdens_init: T'  
Default Value: 
 
Example: 
ddec_classical_hirshfeld T  
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Syntax:  ddec_conv_thresh [Value] [Unit]  
Description:  Threshold for DDEC charges to be considered converged.  
Default Value: 
 
Example: 
ddec_conv_thresh 1e7 e  
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Syntax:  ddec_core_maxit [Value]  
Description:  Maximum number of DDEC core iterations.  
Default Value: 
 
Example: 
ddec_core_maxit 4000  
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Syntax:  ddec_IH_fraction [Value]  
Description:  Fraction of reference ion weighting used in DDEC partitioning.  
Default Value: 
 
Example: 
ddec_IH_fraction 0.5  
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Syntax:  ddec_ih_ionic_range [Value]  
Description:  Range of charges (positive or negative with respect to the neutral atom) to be generated for each ionic species as ionic reference densities. DDEC calculation will exit if the charge on any atom exceeds this range.  
Default Value: 
 
Example: 
ddec_ih_ionic_range 4  
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Syntax:  ddec_interp_rad_dens [Logical]  
Description:  Trilinear postprocessing interpolation of converged DDEC AIM densities for a smoother profile. Does not affect calculation results, only the output density profiles.  
Default Value: 
 
Example: 
ddec_interp_rad_dens T  
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Syntax:  ddec_maxit [Value] [Unit]  
Description:  Maximum number of DDEC iterations.  
Default Value: 
 
Example: 
ddec_maxit 4000  
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Syntax:  ddec_min_shell_dens [Value]  
Description:  Minimum number of points lying in each spherical shell.
Shells with fewer points than this will be subjected to interpolation if 'ddec_interp_rad_dens: T'.  
Default Value: 
 
Example: 
ddec_min_shell_dens 50.0  
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Syntax:  ddec_moment [Value]  
Description:  Calculate DDEC AIM moment of order n. Set to positive integer n to turn on calculation.  
Default Value: 
 
Example: 
ddec_moment 5  
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Syntax:  ddec_multipole [Logical]  
Description:  Calculate DDEC AIM dipoles and quadrupoles.  
Default Value: 
 
Example: 
ddec_multipole T  
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Syntax:  ddec_rad_npts [Value]  
Description:  Number of atomcentered shells used for spherical averaging and storing the DDEC AIM density profiles.  
Default Value: 
 
Example: 
ddec_rad_npts 250  
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Syntax:  ddec_rad_rcut [Value] [Unit]  
Description:  Radius of the largest spherical shell for DDEC analysis. Each spherical shell is spaced equally.  
Default Value: 
 
Example: 
ddec_rad_rcut 6.0 ang  
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Syntax:  ddec_refdens_init [Logical]  
Description:  Initialize DDEC AIM densities as neutral atom reference densities. Required for 'ddec_classical_hirshfeld'.  
Default Value: 
 
Example: 
ddec_refdens_init F  
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Syntax:  ddec_write_rad [Logical]  
Description:  Write converged AIM sphericallyaveraged density profiles for all atoms.  
Default Value: 
 
Example: 
ddec_write_rad T  
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Syntax:  ddec_zero_threshold [Value]  
Description:  Threshold for density on grid to be excluded in order to avoid division by zero.  
Default Value: 
 
Example: 
ddec_zero_threshold 1e8  
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Syntax:  DELTA_E_CONV [Logical]  
Description:  When aggressive density kernel truncation is applied, the energy is not guaranteed to decrease monotonically. When DELTA_E_CONV is true, consecutive energy gains are used as an additional convergence criterion.
 
Default Value: 
 
Example: 
delta_e_conv F  
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Syntax:  DENSE_FOE [Logical]  
Description:  By default the density kernel is calculated in a sparse format in FOE, even when it has no sparsity. If the user wants to apply FOE to systems of less than ~1000 atoms, then using dense matrix algebra may be beneficial.  
Default Value: 
 
Example: 
dense_foe T  
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Syntax:  DENSE_THRESHOLD [Value]  
Description:  Sets the filling fraction threshold above which a section of a sparse matrix will be set to dense. Dense matrix algebra is computationally faster above filling fractions of ~10%, but higher communications bandwidth is required so higher values may degrade performance on lowbandwidth parallel architectures. Most users will not need to change this, but in some cases, a higher value than the default can reduce communications bottlenecks during sparse matrix multiplication.
 
Default Value: 
 
Example: 
dense_threshold 0.80  
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Syntax:  DISPERSION [Integer]  
Description:  Specifies the damping function to be used in the calculation of dispersion corrections:
See Proceedings of the Royal Society A 465(2103), 669683 for more details.
 
Default Value: 
 
Example: 
dispersion 1  
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Syntax:  DOS_SMEAR [Value] [Unit]
 
Description:  Specifies the Gaussian smearing for the density of states calculatedif properties are requested. If the smearing width is negative, the density of states is not calculated.  
Default Value: 
 
Example: 
dos_smear 7 mRy  
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Syntax:  DO_PROPERTIES [Logical]
 
Description:  Enables the calculation of properties including: charge and spin densities, electrostatic potential , Mulliken population analysis , canonical orbitals and energies and density of states.  
Default Value: 
 
Example: 
do_properties T  
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Syntax:  DX_FORMAT [Logical]
 
Description:  Output volumetric data (e.g. charge density, potential, NGWFs, canonical orbitals) in Open DX format. This can be visualized using free software such as OpenDX or VMD.  
Default Value: 
 
Example: 
dx_format T  
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Syntax:  DX_FORMAT_COARSE [Logical]
 
Description:  Makes the .dx files (see DX_FORMAT ) smaller by outputting only odd points along every axis, discarding even points. This allows for smaller output files, eliminates Gibbs ringing.  
Default Value: 
 
Example: 
dx_format_coarse T  
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Syntax:  DX_FORMAT_DIGITS [Integer]
 
Description:  Selects the number of significant digits in .dx file (see DX_FORMAT ) output. This allows for smaller files if some precision can be sacrificed, or to increase output precision of need arises.  
Default Value: 
 
Example: 
dx_format_digits 12  
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Syntax:  EDFT [Logical]
 
Description:  Enable finitetemperature DFT calculations with the EnsembleDFT method. Recommended for calculations on metallic systems.  
Default Value: 
 
Example: 
edft T  
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Syntax:  EDFT_COMMUTATOR_THRES [Value] [Unit]  
Description:  Tolerance threshold for the Hamiltoniandensity matrix commutator during the EDFT inner loop.
 
Default Value: 
 
Example: 
edft_commutator_thres 1.0e6  
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Syntax:  EDFT_ENERGY_THRES [Value] [Unit]  
Description:  Tolerance threshold for the maximum change of the total energy during two consecutive EDFT inner loop iteratrions.
 
Default Value: 
 
Example: 
edft_energy_thres 1.0e4 eV  
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Syntax:  EDFT_ENTROPY_THRES [Value] [Unit]  
Description:  Tolerance threshold for the maximum change of the total entropy during two consecutive EDFT inner loop iteratrions.
 
Default Value: 
 
Example: 
edft_entropy_thres 1.0e5 eV  
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Syntax:  EDFT_EXTRA_BANDS [Integer]
 
Description:  Extra energy bands in EDFT calculations. If set to 0 or a negative number, the total number of bands is equal to the total number of NGWFs. Set to a positive integer to add more energy bands.  
Default Value: 
 
Example: 
edft_extra_bands 16  
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Syntax:  EDFT_FERMI_THRES [Value] [Unit]  
Description:  Tolerance threshold for the maximum change of the Fermi energy during two consecutive EDFT inner loop
 
Default Value: 
 
Example: 
edft_fermi_thres 1.0e4 eV  
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Syntax:  EDFT_FREE_ENERGY_THRES [Value] [Unit]  
Description:  Tolerance threshold for the maximum change of the Helmholtz free energy during two consecutive EDFT inner loop iteratrions.
 
Default Value: 
 
Example: 
edft_free_energy_thres 1.0e4 eV  
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Syntax:  EDFT_INIT_MAXIT [Integer]  
Description:  Maximum number of inner loop iterations with the EDFT method to be performed at the start of the calculation, intended to solve issues with incorrect occupancy schemes after initialisation via Palser Manolopoulos.
 
Default Value: 
 
Example: 
edft_init_maxit 5  
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Syntax:  EDFT_MAXIT [Integer]
 
Description:  Maximum number of inner loop iterations in calculations with the EDFT method.  
Default Value: 
 
Example: 
edft_maxit 5  
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Syntax:  EDFT_MAX_STEP [Value]
 
Description:  Maximum step during the EDFT inner loop line search.  
Default Value: 
 
Example: 
edft_max_step 0.8  
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Syntax:  EDFT_RMS_GRADIENT_THRES [Value]  
Description:  Tolerance threshold for the maximum occupancies RMS gradient during the EDFT inner loop.
 
Default Value: 
 
Example: 
edft_rms_gradient_thres 1.0e5  
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Syntax:  EDFT_ROUND_EVALS [Integer]
 
Description:  Round up the energy eigenvalues to n decimal positions. It helps in calculations where there is a numerical error arising from the grid representation of the NGWFs. If set to a negative number, this directive is ignored.  
Default Value: 
 
Example: 
edft_round_evals 5  
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Syntax:  EDFT_SMEARING_WIDTH [Value] [Unit]  
Description:  Occupation smearing width in EDFT calculations, based on the FermiDirac distribution.
 
Default Value: 
 
Example: 
edft_smearing_width 0.2 eV  
Example: 
edft_smearing_width 800 K (sets the electronic temperature to 800 degree Kelvin)  
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Syntax:  EDFT_SPIN_FIX [Integer]  
Description:  Number of NGWF CG iterations to hold the spin fixed. If negative, hold forever. (Default: 1)
 
Default Value: 
 
Example: 
edft_spin_fix 4  
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Syntax:  EDFT_WRITE_OCC [Logical]
 
Description:  Write the occupancies and the energy levels on disk. If set to true, this directive will generate a .occ file.  
Default Value: 
 
Example: 
edft_write_occ T  
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Syntax:  EIGENSOLVER_ABSTOL [Value]  
Description:  Indicates the precision to which the ScaLapack PDSYGVX eigensolver will resolve the eigenvalues of a matrix. Active only if ONETEP is compiled against ScaLapack. Set to a negative number to use ScaLAPACK default.
 
Default Value: 
 
Example: 
eigensolver_abstol 1.0e5  
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Syntax:  EIGENSOLVER_ORFAC [Value]  
Description:  Indicates the precision to which the ScaLapack PDSYGVX eigensolver will reorthonormalise the eigenvectors of a matrix. Active only if ONETEP is compiled against ScaLapack. Set to a negative number to tell ScaLAPACK to not to perform any kind of orthonormalisation.
 
Default Value: 
 
Example: 
eigensolver_abstol 1.0e3  
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Syntax:  ELD_CALCULATE [Logical]  
Description:  Calculate electron localisation descriptors.  
Default Value: 
 
Example: 
eld_calculate T  
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Syntax:  ELD_FUNCTION [Text]  
Description:  Choose which electron localisation descriptor to use during the properties calculation, either ELF or LOL.  
Default Value: 
 
Example: 
eld_function ELF  
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Syntax:  ELEC_CG_MAX [Integer]  
Description:  Specifies the maximum number of NGWF conjugate gradients iterations between resets.
 
Default Value: 
 
Example: 
elec_cg_max 0 ; steepest descents  
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Syntax:  ELEC_ENERGY_TOL [Value] [Unit]  
Description:  Convergence criterion for minimisation of electronic energy: Energy change per NGWF optimisation iteration must be less than this amount PER ATOM before the calculation is regarded as converged. Ignored if negative.
 
Default Value: 
 
Example: 
elec_energy_tol 0.00001 eV  
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Syntax:  ELEC_FORCE_TOL [Value] [Unit]
 
Description:  Convergence criterion for minimisation of electronic energy: Maximum change in any component of the forces from NGWF optimisation iteration to the next must be less than this amount before the calculation is regarded as converged. Ignored if negative.  
Default Value: 
 
Example: 
elec_force_tol 0.01 "eV/ang"  
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Syntax:  ETRANS_BULK [Logical]  
Description:  Compute the bulk transmission coefficients of the individual leads defined in ETRANS_LEADS.  
Default Value: 
 
Example: 
etrans_bulk T  
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Syntax:  ETRANS_CALCULATE_LEAD_MU [Logical]  
Description:  Calculate the lead chemical potentials via a nonself consistent band structure calculation. The band structure for each lead is written to a .bands file. Defaults to TRUE is ETRANS_EREF_METHOD = LEADS.
 
Default Value: 
 
Example: 
etrans_calculate_lead_mu T  
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Syntax:  ETRANS_ECMPLX [Value] [Unit]  
Description:  Small imaginary part added to the energy in order to impose the appropriate boundary condition to the computed retarded Green's function. This parameter should theoretically tends toward zero. If set too small, instabilities may occur and the calculation of the Green's function may fail.
 
Default Value: 
 
Example: 
etrans_ecmplx 0.00001 hartree  
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Syntax:  ETRANS_EMAX [Value] [Unit]  
Description:  Highest energy for the calculation of the transmission coefficients (defined with respect to the reference level). Transmission coefficients are calculated in the range ETRANS_MIN <= E  ETRANS_EREF <= ETRANS_MAX .
 
Default Value: 
 
Example: 
etrans_emax 0.2 hartree  
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Syntax:  ETRANS_EMIN [Value] [Unit]  
Description:  Lowest energy for the calculation of the transmission coefficients (defined with respect to the reference level). Transmission coefficients are calculated in the range ETRANS_MIN <= E  ETRANS_EREF <= ETRANS_MAX .
 
Default Value: 
 
Example: 
etrans_emin 0.2 hartree  
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Syntax:  ETRANS_ENUM [Integer]  
Description:  Number of energy points equally spaced between ETRANS_EMIN and ETRANS_EMAX for the calculation of the electronic transmission coefficients as a function of the energy.
 
Default Value: 
 
Example: 
etrans_enum 100  
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Syntax:  ETRANS_EREF [Value] [Unit]  
Description:  If ETRANS_EREF_METHOD = REFERENCE, this defines the reference energy about which transmission is calculated. Transmission coefficients are calculated in the range ETRANS_MIN <= E  ETRANS_EREF <= ETRANS_MAX . If any other ETRANS_EREF_METHOD is chosen, this energy is determined automatically according to that method.  
Default Value: 
 
Example: 
etrans_eref 0.0 hartree  
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Syntax:  etrans_eref_method [Text]  
Description:  The method to determine the reference energy for the calculation of transmission coefficients. Options are: LEADS (take the average chemical potential of the leads), REFERENCE (explicitly set the reference energy using ETRANS_EREF ), DIAG (use the midgap level of the entire system). LEADS and REFERENCE are independent of system size. DIAG scales cubically with system size, and will be unsuitable for very large systems. (Calculating the Green's function currently scales cubically also, however a linearscaling recursive algorithm is in development.)  
Default Value: 
 
Example: 
etrans_eref_method REFERENCE  
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Syntax:  ETRANS_LCR [Logical]  
Description:  Compute the 'LeftCentreRight' transmission coefficients between all leads defined in ETRANS_LEADS . Transmission occurs through the device region defined in ETRANS_BULK .  
Default Value: 
 
Example: 
etrans_lcr T  
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Syntax: 
 
Description:  Defines the atoms that form the leads for the calculation of the transport coefficients. Each line of the block defines a lead, consisting of four numbers. The first two numbers define the first and last atom contained within the lead; the second two numbers define the first and last atom that form the principle layer for that lead. The leads should form a bulk periodic unit cell. The atoms in the principle layer should be a periodic repeat, in the same atomic ordering, as the lead atoms. How strictly this is enforced is controlled by ETRANS_LEAD_DISP_TOL .
The principle layer should define the the only set of atoms that the lead interacts with; the lead interacts with the central region through the principle layer. A lead should not directly interact with any other lead. The atoms are ordered by their order in the input file. This block is mandatory when ETRANS_LCR and/or ETRANS_BULK is set to true.  
Default Value:  
Example: 
In this example, three leads are defined containing 36, 60 and 20 atoms.
 
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Syntax:  ETRANS_LEAD_DISP_TOL [Value] [Unit]  
Description:  The maximum acceptable difference in the translation vectors between the atoms in a lead, and the corresponding atoms in the lead principle layer. If the principle layer geometry is an exact repeat of the lead geometry, the translation vectors will all be identical. This parameter allows for this criterion to be relaxed.  
Default Value: 
 
Example: 
etrans_lead_disp_tol 1.0 bohr  
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Syntax:  ETRANS_LEAD_NKPOINTS [Integer]  
Description:  The number of kpoints the lead band structure is calculated for. The kpoints are equally spaced between [0,pi/a].
 
Default Value: 
 
Example: 
etrans_lead_nkpoints 100  
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Syntax:  ETRANS_SAME_LEADS [Logical]  
Description:  Use the same self energy for all leads. If all leads are identical, this may give a very small computational saving. Warning: this may still be a bad approximation for leads with the same geometry.  
Default Value: 
 
Example: 
etrans_same_leads T  
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Syntax: 
 
Description:  Defines the atoms used for the calculation of the transport coefficients. The block should contain a single line giving the index of the first and last atom contained within the transport calculation. All atoms between these indices (inclusive) are included, with all other atoms considered as buffer and ignored. These indices must contain all the leads, and the central scattering region. The atoms are ordered by their order in the input file. This block is mandatory when ETRANS_LCR is set to true.  
Default Value:  
Example: 
In this example, all atoms between 37 and 640 will be used. All other atoms are considered as buffer atoms. Note: This syntax is not compatible with versions earlier than ONETEP 3.3.4
 
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Syntax:  ETRANS_WRITE_HS [Logical]  
Description:  Write the lead and LCR Hamiltonian and Overlap matrices to disk for further analysis. The binary file format description is given in etrans_mod.F90. Warning: these matrices can be very large.  
Default Value: 
 
Example: 
etrans_write_hs T  
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Syntax:  EVEN_PSINC_GRID [Logical]  
Description:  Force even number of points in the simulationcell psinc grid.  
Default Value: 
 
Example:  even_psinc_grid T  
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Syntax:  EXACT_LNV [Logical]
 
Description:  Specifies that the normalization constraint on the density matrix should be imposed exactly, using the purified density kernel (as in the original LiNunesVanderbilt algorithm [Phys. Rev. B47, 10891 (1993)]) rather than the auxiliary kernel (as in the MillamScuseria variant [J. Chem. Phys.106, 5569 (1997)]).  
Default Value: 
 
Example: 
exact_lnv F  
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Syntax:  EXTERNAL_BC_FROM_CUBE [Logical]  
Description:  If this flag is True, external boundary conditions for the electrostatic potential are imposed according to the contents of the cube file rootname_POT_EXT_BC.cube.
This cube file needs to match the dimensions of the FD multigrid (see the implicit solvation documentation for more details).  
Default Value: 
 
Example: 
external_bc_from_cube : T  
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Syntax:  EXTERNAL_PRESSURE [Physical]  
Description:  Value of the input pressure Pin in the electronic enthalpy functional H=U+PV where U is the total KohnSham internal energy of the system and V is a volume definition based on an electronicdensity isosurface (determined by the SMOOTHING_FACTOR and ISOSURFACE_CUTOFF keywords). The electronic enthalpy can be minimized selfconsistently during geometry relaxation or MD runs and allows for constant pressure simulation of finite systems [Cococcioni et al, Phys. Rev. Lett.94, 145501 (2005)]. The implementation is described in more detail in [Corsini et al, J. Chem. Phys. 2013, 139, 084117].  
Default Value: 
 
Example:  external_pressure 1.0 gpa  
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Syntax:  EXTRA_N_SW [Integer]
 
Description:  Generates extra spherical waves for the NGWFs representation. The extra SW will suffer of aliasing as their frequency is higher than the maximum plane waves basis set given by the kinetic cutoff.  
Default Value: 
 
Example: 
extra_n_sw 10  
Example: 
extra_n_sw 5  
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Syntax:  FFTBOX_BATCH_SIZE [Int]  
Description:  Number of NGWFs in each batch of fftboxes.  
Default Value: 
 
Example: 
fftbox_batch_size 8  
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Syntax:  FFTBOX_PREF [Text]
 
Description:  Specifies a size for the FFTbox that is preferable to the smallest possible size that would normally be chosen (e.g. if the FFT library on a particular machine favours certain sizes). The FFTbox is specified by three integers (which must all be odd) that give the number of coarse grid points in thea1,a2anda3directions respectively.  
Default Value: 
 
Example: 
fftbox_pref 65 65 65  
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Syntax:  FINE_GRID_SCALE [Real]
 
Description:  Specifies the spacing of the fine grid as a multiple of the spacing of the standard grid (which is determined by psinc_spacing or by cutoff_energy).  
Default Value: 
 
Example: 
fine_grid_scale 4.0  
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Syntax:  FOE [Logical]  
Description:  Enable calculation of the density kernel with a Fermi Operator Expansion approach in finitetemperature DFT calculations with the EnsembleDFT method. This method is recommended when the calculation contains more than ~1000 atoms. EDFT should also be enabled.  
Default Value: 
 
Example: 
foe T  
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Syntax:  FOE_AVOID_INVERSIONS [Logical]  
Description:  In the FOE method, several matrix inversions are necessary to calculate the finite temperature density kernel. If this parameter is enabled, the matrix solves are instead approximated by Chebyshev expansions. This may be more accurate with a given sparsity pattern, but is likely to be slightly slower than calculating the inverses iteratively.  
Default Value: 
 
Example: 
foe_avoid_inversions T  
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Syntax:  FOE_CHEBY_THRES [Real]  
Description:  When the FOE method builds up an approximation for the density kernel in powers of the Hamiltonian matrix, the maximum term in the Chebyshev expansion is determined by this parameter.  
Default Value: 
 
Example: 
foe_cheby_thres 1.0e10  
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Syntax:  FOE_CHECK_ENTROPY [Logical]  
Description:  In the FOE method, the entropy matrix is also calculated as an expansion (in powers of the density kernel) to calculate the entropy itself. This expansion is prone to divergence, so to check for this, and to correct it if it happens, the result is checked against a simple quadratic approximation to the entropy matrix which cannot diverge.  
Default Value: 
 
Example: 
foe_check_entropy T  
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Syntax:  FOE_MU_TOL [Value] [Unit]  
Description:  The performance of the FOE method is affected strongly by how accurately the chemical potential is determined. This parameter should be tuned by the user to find an accurate energy, while minimising the number of iterations in FOE.  
Default Value: 
 
Example: 
foe_mu_tol 1.0e9 hartree  
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Syntax:  FOE_TEST_SPARSITY [Value]  
Description:  If using the AQuAFOE method, the sparsity pattern is mainly determined by the NGWF radii. To determine the accuracy of this approximation, this parameter can be enabled to print out an estimate.  
Default Value: 
 
Example: 
foe_test_sparsity F hartree  
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Syntax:  GEOM_BACKUP_ITER [Integer]
 
Description:  Specifies the backup frequency for geometry optimisation. If the input filename is rootname.dat then the backup filename is rootname.continuation .  
Default Value: 
 
Example: 
geom_backup_iter 5  
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Syntax:  GEOM_CONTINUATION [Logical]
 
Description:  Continue a geometry optimization from a previous run using the .continuation backup file.  
Default Value: 
 
Example: 
geom_continuation T  
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Syntax:  GEOM_CONVERGENCE_WIN [Integer]
 
Description:  Specifies the number of consecutive iterations during which the convergence criteria must be met.  
Default Value: 
 
Example: 
geom_convergence_win 3  
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Syntax:  GEOM_DISP_TOL [Value] [Unit]  
Description:  Specifies atomic displacement tolerance used as one of the criteria for convergence of geometry optimization. The positions of all atoms must change by less than this tolerance to satisfy this criterion.
 
Default Value: 
 
Example: 
geom_disp_tol 1.0e4 nm  
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Syntax:  GEOM_ENERGY_TOL [Value] [Unit]  
Description:  Specifies the tolerance for enthalpy per atom over the convergence window as a criterion for geometry optimization convergence.
 
Default Value: 
 
Example: 
geom_energy_tol 0.2 meV  
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Syntax:  GEOM_FORCE_TOL [Value] [Unit]  
Description:  Specifies the tolerance for maximum atomic force as a criterion for geometry optimization convergence. Note that units involving a forward slash (/) must be quoted as in the example below.
 
Default Value: 
 
Example: 
geom_force_tol 0.1 "ev/ang"  
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Syntax:  GEOM_FREQUENCY_EST [Value] [Unit]  
Description:  Specifies the estimated average phonon frequency (as an energy) used to initialize the inverse Hessian matrix for geometry optimization.
 
Default Value: 
 
Example: 
geom_frequency_est 0.2 eV  
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Syntax:  GEOM_LBFGS [Logical]  
Description:  If the history length (GEOM_LBFGS_MAX_UPDATES) is set to 0 then LBFGS will perform a geometry optimisation equivalent to the BFGS method. If combined with a limited history length, however, it will store only the latest number of history vectors of length nDOF (number of degrees of freedom) rather than nDOF^2 of them. This potentially allows for larger calculations, where storage of the full Hessian matrix is impossible.
 
Default Value: 
 
Example: 
geom_lbfgs F  
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Syntax:  GEOM_LBFGS_BLOCK_LENGTH [Integer]  
Description:  If LBFGS is performed in unbounded mode, then the geometry optimiser should perform identically to BFGS, however, to avoid using as much memory as BFGS, the number of history vectors which are stored is increased in increments of GEOM_LBFGS_BLOCK_LENGTH. So, provided that the number of iterations of the geometry optimiser does not reach ~1/2 * number of degrees of freedom, then it will use less memory than a standard BFGS calculation.
 
Default Value: 
 
Example: 
geom_lbfgs_block_length 30  
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Syntax:  GEOM_LBFGS_MAX_UPDATES [Integer]  
Description:  The LBFGS method can optionally limit the number of history vectors which it uses to build an approximation to he inverse Hessian to the latest N. This can vastly reduce the memory requirements if N is small, but the user should ensure that N is large enough that the approximation is sufficient. If N is set to 0 then LBFGS keeps an unlimited history, which is equivalent to BFGS.
 
Default Value: 
 
Example: 
geom_lbfgs_max_updates 30  
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Syntax:  GEOM_MAX_ITER [Integer]  
Description:  Specifies the maximum number of iterations for geometry optimisation.
 
Default Value: 
 
Example: 
geom_max_iter 30  
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Syntax:  GEOM_METHOD [Text]
 
Description:  Specifies the method for geometry optimisation, currently either CARTESIAN for the BFGS algorithm based on Cartesian atomic coordinates [e.g. Pfrommeret al.,J. Comp. Phys.131, 233 (1997)] or DELOCALIZED for delocalized internal coordinates [Andzelm et al., Chem. Phys. Lett., 335, 321, (2001)].  
Default Value: 
 
Example: 
geom_method DELOCALIZED  
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Syntax:  GEOM_MODULUS_EST [Value] [Unit]  
Description:  Specifies the estimated bulk modulus used to initialize the inverse Hessian matrix for geometry optimization.
 
Default Value: 
 
Example: 
geom_modulus_est 100 GPa  
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Syntax:  GEOM_PRECOND_EXP_A [Real]  
Description:  This is a parameter in the EXP geometry optimisation preconditioning scheme explained in:
Packwood, David, et al. "A universal preconditioner for simulating condensed phase materials." The Journal of Chemical Physics 144.16 (2016): 164109. The convergence of the geometry optimisation is "relatively insensitive" to this parameter, but it can be tweaked to obtain slightly faster convergence if desired.  
Default Value: 
 
Example: 
geom_precond_EXP_A 3.0  
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Syntax:  GEOM_PRECOND_EXP_C_STAB [Value] [Unit]  
Description:  Specifies a diagonal contribution to add onto the ionic part of the Hessian preconditioning matrix in LBFGS / EXP preconditioning. This can improve stability if increased in magnitude, but should be left alone if the geometry optimisation is converging.  
Default Value: 
 
Example: 
geom_precond_exp_c_stab 0.15 ha/bohr**2  
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Syntax:  GEOM_PRECOND_EXP_MU [Value] [Unit]  
Description:  This preconditioner scaling parameter is calculated automatically if set to the default value of 0. The value found automatically is not guaranteed to give the best convergence, but has performed well empirically. The user may experiment with values to give faster convergence.  
Default Value: 
 
Example: 
geom_precond_exp_mu 0.1 ha/bohr**2  
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Syntax:  GEOM_PRECOND_EXP_R_CUT [Value] [Unit]  
Description:  Specifies an upper limit in atomic separation to consider when calculating terms in the preconditioning matrix, with LBFGS / EXP preconditioning. A lower value is faster, but a larger value will give a potentially better preconditioning matrix. This is calculated from the nearest neighbour distance GEOM_PRECOND_EXP_R_NN by default.  
Default Value: 
 
Example: 
geom_precond_exp_r_cut 4.0 bohr  
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Syntax:  GEOM_PRECOND_EXP_R_NN [Value] [Unit]  
Description:  If set to 0.0, as it is by default, the nearest neighbour distance is calculated automatically. This is used to calculate the distance cutoff in the EXP LBFGS preconditioner.  
Default Value: 
 
Example: 
geom_precond_exp_r_NN 4.0 bohr  
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Syntax:  GEOM_PRECOND_FF_C_STAB [Value] [Unit]  
Description:  Specifies a diagonal contribution to add onto the ionic part of the Hessian preconditioning matrix in LBFGS / FF preconditioning. This can improve stability if increased in magnitude, but should be left alone if the geometry optimisation is converging.  
Default Value: 
 
Example: 
geom_precond_ff_c_stab 0.15 ha/bohr**2  
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Syntax:  GEOM_PRECOND_FF_R_CUT [Value] [Unit]  
Description:  Specifies an upper limit in atomic separation to consider when calculating terms in the preconditioning matrix, with LBFGS / FF preconditioning. A lower value is faster, but a larger value will give a potentially better preconditioning matrix.  
Default Value: 
 
Example: 
geom_precond_ff_r_cut 4.0 bohr  
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Syntax:  GEOM_PRECOND_TYPE [Text]  
Description:  If this is set to NONE, then LBFGS will use the Pfrommer preconditioner as normal. If it is set to ID, then a scaled identity matrix will be used as the preconditioning matrix. If set to EXP, then an exponential preconditioner will be used which can reduce the number of geometry iterations in inorganic calculations to less than half. For organic calculations, the FF, forcefield preconditioning method is recommended which can reduce the number of geometry iterations to about a third of the number with geom_precond_type : F. The FF method does not support atomic species beneath row 3 in the periodic table. More information on these methods may be found in :
Packwood, David, et al. "A universal preconditioner for simulating condensed phase materials." The Journal of Chemical Physics 144.16 (2016): 164109.  
Default Value: 
 
Example: 
geom_precond_type EXP  
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Syntax:  GEOM_PRINT_INV_HESSIAN [Logical]
 
Description:  Include information about the inverse Hessian matrix in the ouput of a geometry optimization.  
Default Value: 
 
Example: 
geom_print_inv_hessian T  
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Syntax:  GEOM_RESET_DK_NGWFS_ITER [Integer]
 
Description:  Number of geom iterations between resets of kernel and NGWFs  
Default Value: 
 
Example: 
geom_reset_dk_ngwfs_iter 20  
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Syntax:  GEOM_REUSE_DK_NGWFS [Logical]  
Description:  Reuse density kernel and NGWFs during geometry optimisation steps
 
Default Value: 
 
Example: 
geom_reuse_dk_ngwfs F  
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Syntax:  GRD_FORMAT [Logical]  
Description:  Output volumetric data (e.g. charge density, potential, NGWFs, canonical orbitals) in .grd format used by Accelrys Materials Studio .
 
Default Value: 
 
Example: 
grd_format F  
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Syntax:  H2DENSKERN_SPARSITY [Logical]  
Description:  Enable the AQuAFOE method when FOE and EDFT are both enabled. This allows the sparsity of the density kernel to be adjusted by the NGWF radii. This approach should be faster for calculations with > 1000 atoms, and explicitly allows sparsity in the density kernel.  
Default Value: 
 
Example: 
h2denskern_sparsity T  
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Syntax:  HOMO_DENS_PLOT [Integer]  
Description:  Specifies the number of canonical orbitals below the HOMO to plot, if DO_PROPERTIES is set to true. Thus a value of zero plots only the HOMO, a negative value disables plotting and a positive value of N plots the N+1 highest occupied canonical orbitals.
 
Default Value: 
 
Example: 
homo_dens_plot 0  
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Syntax:  HOMO_PLOT [Integer]
 
Description:  Specifies the number of canonical orbitals below the HOMO to plot, if DO_PROPERTIES is set to true. Thus a value of zero plots only the HOMO, a negative value disables plotting and a positive value of N plots the N+1 highest occupied canonical orbitals.  
Default Value: 
 
Example: 
homo_plot 0  
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Syntax:  HUBBARD [Block]  
Syntax: 
 
Description:  Applies the DFT+U, also known as LDA+U, correction for strongly correlated materials. For species S and correlated subspace of angular momentum channel L (with principal quantum number n=L+1 ) we apply a DFT+U correction with Hubbard parameter U (eV) and exchange parameter J (eV). Standard DFT+U functionality can be obtained by setting J=0 .
The effective nuclear charge Z determines how the projectors defining the correlated subspace are generated. If any negative value is given, e.g., Z=10 , the NGWF initial guess orbitals (numerical atomic orbitals) are used. Alternatively, a positive value of Z causes the code to generate hydrogenic orbitals spanning this space with effective nuclear charge Z .
The a and s parameters (eV) are a rigid potential shift and a spinsplitting, respectively, applied to the subspaces.
For more information, please read the file in the documentation section.  
Default Value:  
Example: 
 
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Syntax:  HUBBARDSCF_ON_THE_FLY [Logical]  
Description:  Activate a nonvariational onthefly form of projector selfconsistency in DFT+U or cDFT, in which the projectors are updated whenever the NGWFs are. task : HUBBARDSCF is then not needed.  
Default Value: 
 
Example: 
hubbardscf_on_the_fly T  
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Syntax:  HUBBARD_CONV_WIN [Integer]  
Description:  The minimum number of Hubbard projector update steps satisfying the incremental energy tolerance HUBBARD_ENERGY_TOL required for convergence in task : HUBBARDSCF.  
Default Value: 
 
Example: 
hubbard_conv_win 4  
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Syntax:  HUBBARD_ENERGY_TOL [Value] [Unit]  
Description:  The maximum incremental energy change between Hubbard projector update steps allowed for converge in task : HUBBARDSCF.  
Default Value: 
 
Example: 
hubbard_energy_tol 1.0E4 eV  
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Syntax:  HUBBARD_FUNCTIONAL [Real]  
Description:  The form of DFT+U energy term used. Contact developers if you need to try something beyond the default.  
Default Value: 
 
Example: 
hubbard_functional 1  
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Syntax:  HUBBARD_MAX_ITER [Integer]  
Description:  The maximum allowed number of Hubbard projector update steps taken in a projector selfconsistent DFT+U or cDFT calculation in task : HUBBARDSCF.  
Default Value: 
 
Example: 
hubbard_max_iter 6  
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Syntax:  HUBBARD_NGWF_SPIN_THRESHOLD [Value] [Unit]  
Description:  The incremental change in energy, in totalenergy minimisation, at which any spinsplitting (Zeeman) type term in DFT+U is switched off, and the minimisation history reset. Useful for breaking openshell, antiferromagnetic, or chargedensity wave symmetries.  
Default Value: 
 
Example: 
hubbard_ngwf_spin_threshold 1.0E3 eV  
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Syntax:  HUBBARD_PROJ_MIXING [Real]  
Description:  The fraction of previous Hubbard projector to mix with new for projector selfconsistent DFT+U or cDFT in task : HUBBARDSCF. Not found to be necessary.  
Default Value: 
 
Example: 
hubbard_proj_mixing 0.2  
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Syntax:  HUBBARD_READ_PROJECTORS [Logical]  
Description:  Read Hubbard projectors from .tightbox_hub_projs file in restart calculations involving DFT+U.  
Default Value: 
 
Example: 
hubbard_read_projectors T  
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Syntax:  HUBBARD_TENSOR_CORR [Integer]  
Description:  The form of correction used to correct for any nonorthogonality between Hubbard projectors. Contact developers if you need to try something other than the default "tensorial" correction.  
Default Value: 
 
Example: 
hubbard_tensor_corr 1  
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Syntax:  IMAGE_SIZES [Text]  
Description:  If specified in the input file, a string of the format ‘ijklm...’ can be used to individually size the images in an imageparallel run. The number of sections specified should be equal the number of images in the run and the sum of the image sizes should be equal the number of MPI processes specified at runtime.  
Default Value: 
 
Example: 
image_sizes 3354  
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Syntax:  INITIAL_DENS_REALSPACE [Logical]  
Description:  Specifies whether to construct the initial density passed to PalserManolopoulos (or diagonalisation) in realspace, from the sum of the atomsolver densities (if true), or the default of a superposition of gaussians (if false).
 
Default Value: 
 
Example: 
initial_dens_realspace T  
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Syntax:  ISOSURFACE_CUTOFF [Value]  
Description:  Determines the cutoff density alpha of the electronic density isosurface defining the volume Ve used in the electronic enthalpy method. Care must be taken to calibrate its value, along with SMOOTHING_FACTOR, for the system of interest as described in [Corsini et al, J. Chem. Phys. 2013, 139, 084117]  
Default Value: 
 
Example:  isosurface_cutoff 0.0003  
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Syntax:  IS_APOLAR_SCALING_FACTOR [Value]  
Description:  Controls the scaling of the apolar term with the aim of taking solutesolvent dispersionrepulsion into account. This is only relevant in implicit solvent calculations.
 
Default Value: 
 
Example: 
IS_APOLAR_SCALING_FACTOR 1.0  
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Syntax:  IS_AUTO_SOLVATION [Logical]  
Description:  Specifies that a calculation in vacuum should be automatically performed before any calculation that employs implicit solvent.
 
Default Value: 
 
Example: 
is_auto_solvation T  
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Syntax:  IS_BC_COARSENESS [Integer]
 
Description:  Specifies the edge length of the cubic block, in units of fine grid delta, over which charge will be coarsegrained in the calculation of open boundary conditions. This is only relevant in implicit solvent calculations and in calculations with open boundary conditions (such as calculations with smeared ions).  
Default Value: 
 
Example: 
is_bc_coarseness 7 ; Use blocks 7x7x7  
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Syntax:  IS_BC_SURFACE_COARSENESS [Integer]
 
Description:  Specifies the edge length of the square block, in units of fine grid delta, over which the potential will be bilinearly interpolated in the calculation of open boundary conditions. This is only relevant in implicit solvent calculations and in calculations with open boundary conditions (such as calculations with smeared ions). Values larger than 1 will speed up the calculation but can impact accuracy for charged systems  use with care.  
Default Value: 
 
Example: 
is_bc_surface_coarseness 3 ; Use surface blocks of 3x3  
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Syntax:  IS_BC_THRESHOLD [Real]  
Description:  Specifies the charge density threshold used for coarsegraining in the calculation of open boundary conditions. Fine grid points with charge magnitudes below this threshold will be ignored during the coarsegraining procedure. This serves to eliminate the unnecessary integration of noise and ringing. Decreasing this threshold (to, say, 1E10) might be necessary in rare situations, such as in runs using simulation cells with inadequate padding and fine_grid_scale > 2.0, which may lead to more severe ringing. Increasing this threshold mainly serves to increase performance, however, accuracy will be impacted if this threshold is set too high (higher than, say, 5E8).
This is only relevant in implicit solvent calculations and in calculations with open boundary conditions (such as calculations with smeared ions).
 
Default Value: 
 
Example: 
is_bc_threshold 1E10 ; Be extra accurate  
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Syntax:  IS_BULK_PERMITTIVITY [Value]  
Description:  Sets the relative dielectric permittivity of the solvent.
 
Default Value: 
 
Example: 
IS_BULK_PERMITTIVITY 14.2 ; ethanediamine as solvent  
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Syntax:  IS_CHECK_SOLV_ENERGY_GRAD [Logical]  
Description:  Checks the gradient of solvation energy with finite differences. This is only relevant in implicit solvent calculations.
 
Default Value: 
 
Example: 
IS_CHECK_SOLV_ENERGY_GRAD T  
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Syntax:  IS_CORE_WIDTH [Physical]  
Description:  Only used in implicit solvent calculations. In the IS model used in ONETEP the dielectric permittivity is a function of electronic density. For certain atoms (e.g. Pt) the use of pseudopotentials may cause the electronic density in the immediate vicinity of an atom to be so low as to produce permittivities that nonnegligibly differ from 1. By using this directive you can specify a radius around each core where the permittivity is set to unity regardless of the usual definition of eps=eps(rho). We've not yet seen a case where the default would be unsuitable.  
Default Value: 
 
Example: 
is_core_width 1.4 bohr  
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Syntax:  IS_DENSITY_THRESHOLD [Value]  
Description:  Sets the value of the rho_0 parameter (in atomic units) in the definition of the dielectric cavity as described in DA Scherlis, JL Fattebert, F Gygi, M Cococcioni, and N Marzari, Journal of Chemical Physics 124, 074103 (2006). This is only relevant in implicit solvent calculations.
 
Default Value: 
 
Example: 
IS_DENSITY_THRESHOLD 0.00035  
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Syntax: 
 
Description:  In typical applications this block can be absent. If not absent, it is used to determine which additional parts of the system are inaccessible to the implicit solvent.
 
Default Value: 
 
Example: 
 
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Syntax:  is_dielectric_exclusions_smear [Value] [Unit]  
Description:  Length scale that defines the extent of the smearing of dielectric exclusion region boundaries. For more details, see the implicit solvation documentation.  
Default Value: 
 
Example: 
is_dielectric_exclusions_smear 0.5 Bohr
 
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Syntax:  IS_DIELECTRIC_FUNCTION [FGF  GAUSSIAN]
 
Description:  Chooses the function used to generate the dielectric cavity from the electronic density. FGF uses the one described in DA Scherlis, JL Fattebert, F Gygi, M Cococcioni, and N Marzari, Journal of Chemical Physics 124, 074103 (2006). GAUSSIAN uses the core density to generate the cavity, this is not currently supported. This is only relevant in implicit solvent calculations.  
Default Value: 
 
Example: 
IS_DIELECTRIC_FUNCTION FGF  
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Syntax:  IS_DIELECTRIC_MODEL [FIX_INITIAL  SELF_CONSISTENT  GAUSSIAN_IONS]
 
Description:  Chooses how the dielectric cavity responds to changes in the electronic density. With FIX_INITIAL the cavity remains fixed (and the calculation is still selfconsistent). With SELF_CONSISTENT , the cavity selfconsistently reacts to changes in the density. With GAUSSIAN_IONS the core density is used to generate the cavity, so it remains fixed as well. GAUSSIAN_IONS is not currently supported. FIX_INITIAL is strongly recommended. SELF_CONSISTENT offers slightly improved accuracy, but requires very fine grids to converge (such as FINE_GRID_SCALE 4.0 ), which translates into extremely high memory requirements  thus it is not recommended, unless for very small molecules. This keyword is only relevant in implicit solvent calculations.  
Default Value: 
 
Example: 
IS_DIELECTRIC_MODEL SELF_CONSISTENT  
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Syntax:  IS_DISCRETIZATION_ORDER [Integer]  
Description:  Sets the discretization order used for finitedifferences. The available orders are: 2, 4, 6, 8, 10 and 12. Recommended is 8 or 10. Currently this keyword is only relevant in multigrid calculations (which are those using implicit solvent or open boundary conditions), where it controls the discretization order used for defectcorrecting the multigrid solution and for calculating gradients and laplacians.
 
Default Value: 
 
Example: 
IS_DISCRETIZATION_ORDER 10  
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Syntax:  IS_HC_STERIC_CUTOFF [Physical]  
Description:  Specifies the cutoff radius for the hardcore steric potential in implicit solvation with Boltzmann ions. Only relevant for implicit solvation calculations with nonzero salt concentrations. The Boltzmann ions are never allowed within IS_HC_STERIC_CUTOFF from any phyiscal ionic core, or in other words, the solvent ionic accessibility is zero there, and 1 elsewhere. The value will dramatically impact obtained results. Compare: IS_SC_STERIC_CUTOFF .  
Default Value: 
 
Example: 
is_hc_steric_cutoff 3.5 bohr  
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Syntax:  IS_IMPLICIT_SOLVENT [Logical]  
Description:  Turns the implicit solvent on or off. As the implicit solvent requires the smeared ion representation, it also sets IS_SMEARED_ION_REP to T . When on, open boundary conditions are used for the calculation of ionion, Hartree and local pseudopotential terms.
 
Default Value: 
 
Example: 
IS_IMPLICIT_SOLVENT T  
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Syntax:  IS_INCLUDE_APOLAR [Logical]  
Description:  When T , includes the apolar term in an implicit solvent calculation. Can only be used with IS_IMPLICIT_SOLVENT T .
 
Default Value: 
 
Example: 
IS_INCLUDE_APOLAR F  
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Syntax:  IS_INCLUDE_CAVITATION [Logical]  
Description:  When T , includes the cavitation term in an implicit solvent calculation. Can only be used with IS_IMPLICIT_SOLVENT T .
 
Default Value: 
 
Example: 
IS_INCLUDE_CAVITATION F  
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Syntax:  IS_MULTIGRID_DEFECT_ERROR_TOL [Value]  
Description:  Sets the error tolerance for the defectcorrection algorithm in a multigrid calculation. This controls the maximum error when solving the defect equation in every defectcorrection iteration and is *not* directly related to the magnitude of the error in the final solution. This keyword is only relevant in multigrid calculations (which are those using implicit solvent or open boundary conditions).
 
Default Value: 
 
Example: 
IS_MULTIGRID_DEFECT_ERROR_TOL 1E4 ; Try a stricter tolerance in case defectcorrection diverges  
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Syntax:  is_multigrid_error_damping [Boolean]  
Description:  Turns on error damping in the multigrid defectcorrection procedure. This is useful for solving the full (nonlinearised) PoissonBoltzmann equation, but will likely not do much for the linearised PBE or for the Poisson equation.  
Default Value: 
 
Example: 
is_multigrid_error_damping T  
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Syntax:  IS_MULTIGRID_ERROR_TOL [Value]  
Description:  Sets the error tolerance for the solution obtained through multigrid. If IS_DISCRETIZATION_ORDER is larger than 2, this is the final error obtained after defect correction, otherwise this is the error of the uncorrected multigrid solution. This keyword is only relevant in multigrid calculations (which are those using implicit solvent or open boundary conditions).
 
Default Value: 
 
Example: 
IS_MULTIGRID_ERROR_TOL 1E4 ; Try a relaxed tolerance to speed calculation up  
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Syntax:  IS_MULTIGRID_MAX_ITERS [Integer]  
Description:  Sets the maximum number of iterations for the multigrid calculation. This controls both the maximum number of defectcorrection steps and the maximum number of iterations of the multigrid process in each defectcorrection step (and in the first solution with 2nd order, prior to defect correction). This value is best left at its default. This keyword is only relevant in multigrid calculations (which are those using implicit solvent or open boundary conditions).
 
Default Value: 
 
Example: 
IS_MULTIGRID_MAX_ITERS 200 ; purposefully waste time  
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Syntax:  IS_MULTIGRID_NLEVELS [Integer]  
Description:  Sets the number of multigrid levels for a multigrid calculation. This keyword is only relevant in multigrid calculations (which are those using implicit solvent or open boundary conditions).
 
Default Value: 
 
Example: 
IS_MULTIGRID_NLEVELS 3  
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Syntax:  IS_MULTIGRID_VERBOSE [Logical]  
Description:  Output crosssetions of quantities that are of interest during multigrid calculations to text files. For instance it might be desirable to examine the permittivity to verify whether a pocket in a molecule is solventacessible or not. The cross sections are always performed along the X direction, for a given value of Y and Z.  
Default Value: 
 
Example: 
is_multigrid_verbose T  
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Syntax:  IS_MULTIGRID_VERBOSE_Y [physical]  
Description:  Specifies the offset along the Y axis for crosssections performed with IS_MULTIGRID_VERBOSE . Make sure you provide units. Compare IS_MULTIGRID_VERBOSE_Z  
Default Value: 
 
Example: 
IS_MULTIGRID_VERBOSE_Y 14.5 bohr  
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Syntax:  IS_MULTIGRID_VERBOSE_Y [physical]  
Description:  Specifies the offset along the Z axis for crosssections performed with IS_MULTIGRID_VERBOSE . Make sure you provide units. Compare IS_MULTIGRID_VERBOSE_Y  
Default Value: 
 
Example: 
IS_MULTIGRID_VERBOSE_Y 14.5 bohr  
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Syntax:  IS_PBE [NONELINEARISEDFULL]  
Description:  Chooses the equation to be solved in implicit solvation. NONE chooses the nonomogeneous Poisson equation (NPE), LINEARISED chooses the linearised PoissonBoltzmann equation, FULL chooses the full (nonlinearised) PoissonBoltzmann equation.  
Default Value: 
 
Example: 
is_pbe FULL  
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Syntax:  IS_PBE_BC_DEBYE_SCREENING [Boolean]  
Description:  Specifies whether boundary conditions in implicit solvation should use Debye screening (lambda*exp) factor. This is only relevant for implicit solvation calculations using the PoissonBoltzmann formulation. This screening is exact in the linearised formulation, and an approximation in the full formulation.  
Default Value: 
 
Example: 
is_pbe_bc_debye_screening F  
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Syntax:  IS_PBE_EXP_CAP [Double]  
Description:  Sets a numerical cap at the arguments in the exp() in PoissonBoltzmann terms in implicit solvation. If this keyword is specified, and uses a value different from 0.0, every argument of an exp() function in PoissonBoltzmann implicit solvation will be checked against the cap and replaced with the value of the cap if it exceeds the cap. This is a crude way of preventing runaway nonlinearities.
Note that DL_MG internally caps the cap (!) at max_expcap =50.0, while on the ONETEP side any positive value can be used for the cap. Thus, using values larger that 50.0 will lead to an inconsistency. Anyway, exp(50.0) > 5E21, so tread carefully.  
Default Value: 
 
Example: 
is_pbe_exp_cap 20.0  
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Syntax:  is_pbe_temperature [Double]  
Description:  Sets the temperature for the Boltzmann term in implicit solvation. Has no effect if IS_PBE is set to NONE or if implicit solvation is not in use.  
Default Value: 
 
Example: 
is_pbe_temperature 300.0  
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Syntax:   
Description:  Specifies whether the full aproximation scheme (FAS) should be used for the solution of the PoissonBoltzmann equation in implicit solvation.  
Default Value: 
 
Example: 
is_pbe_use_fas T  
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Syntax:  IS_SC_STERIC_CUTOFF [Physical]  
Description:  Specifies the cutoff radius for the softcore steric potential in implicit solvation with Boltzmann ions. Only relevant for implicit solvation calculations with nonzero salt concentrations. This works vastly differently than the hardcore steric potential (compare IS_HC_STERIC_CUTOFF )  here this parameter controls mostly computational efficiency, as the softcore steric potential is only generated within IS_SC_STERIC_CUTOFF from each physical ion core, and assumed to be zero elsewhere. This ensures linear scaling behaviour. The actual values of the steric potentials are controlled via IS_SC_STERIC_MAGNITUDE and IS_SC_STERIC_SMOOTHING_ALPHA . The potential is shifted down by the value at IS_STERIC_CUTOFF to avoid discontinuities.  
Default Value: 
 
Example: 
is_sc_steric_cutoff 12.0 bohr  
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Syntax:  is_sc_steric_magnitude [Physical]  
Description:  Prefactor A in softcore steric potential in implicit solvation with Boltzmann ions. The softcore potential is the repulsive part of the LJ potential, i.e. A/r^12 centred around each ion, smoothed by multiplying by erf(IS_SC_STERIC_SMOOTHING_ALPHA *r)^12, then truncated at a truncation radius of IS_SC_STERIC_CUTOFF , and shifted by a tiny amount to be zero at the truncation radius, to avoid a discontinuity.  
Default Value: 
 
Example: 
is_sc_steric_magnitude 2000 Ha*bohr^12  
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Syntax:  IS_SC_STERIC_SMOOTHING_ALPHA [Physical]  
Description:  Smoothing factor alpha in softcore steric potential in implicit solvation with Boltzmann ions. The softcore potential is the repulsive part of the LJ potential, i.e. IS_STERIC_MAGNITUDE /r^12 centred around each ion, smoothed by multiplying by erf(alpha*r)^12, then truncated at a truncation radius of IS_STERIC_CUTOFF , and shifted by a tiny amount to be zero at the truncation radius, to avoid a discontinuity.  
Default Value: 
 
Example: 
is_sc_steric_smoothing_alpha 1.2 bohr^1  
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Syntax:  IS_SEPARATE_RESTART_FILES [Logical]  
Description:  Causes the solute cavity used in implicit solvation calculations to be constructed from a separate set of restart files (.vacuum_dkn, .vacuum_tightbox_ngwfs) from those that are used to restart the calculation itself (.dkn, .tightbox_ngwfs).
 
Default Value: 
 
Example: 
IS_SEPARATE_RESTART FILES T  
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Syntax:  IS_SMEARED_ION_REP [Logical]  
Description:  Turns the smeared ion representation on or off. All smeared ion calculations are performed in open boundary conditions. Turning on the smeared ion representation is a necessary condition for performing implicit solvent calculations. Calculations in vacuum that will serve as reference calculations for calculations in solvent should also used smeared ions. Smeared ions are not compatible with cutoff Coulomb (COULOMB_CUTOFF_TYPE ) or MartynaTuckerman (PBC_CORRECTION_CUTOFF ), which are other ways of realizing open boundary conditions.
 
Default Value: 
 
Example: 
IS_SMEARED_ION_REP T  
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Syntax:  IS_SMEARED_ION_WIDTH [Value] [Unit]  
Description:  Sets the smearing width for smeared ions. This is only relevant when IS_SMEARED_ION_REP is @T@. Values larger than default, especially larger than 1.0 bohr, are likely to lead to nonphysical results in implicit solvent calculations. Values smaller than default, especially smaller than 0.6 bohr will negatively impact the convergence of the multigrid.
 
Default Value: 
 
Example: 
IS_SMEARED_ION_WIDTH 0.6 bohr  
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Syntax:  IS_SOLVATION_BETA [Value]
 
Description:  Sets the value of the beta parameter (unitless) in the definition of the dielectric cavity as described in DA Scherlis, JL Fattebert, F Gygi, M Cococcioni, and N Marzari, Journal of Chemical Physics 124, 074103 (2006). This is only relevant in implicit solvent calculations.  
Default Value: 
 
Example: 
IS_SOLVATION_BETA 1.6  
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Syntax:  IS_SOLVATION_METHOD [DIRECT  CORRECTIVE]
 
Description:  Chooses either the direct approach or a corrective approach to solving the Poisson equation in solvent. This keyword is reserved for future development, CORRECTIVE is not currently implemented. This is only relevant in implicit solvent calculations.  
Default Value: 
 
Example: 
IS_SOLVATION_METHOD DIRECT  
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Syntax:  IS_SOLVATION_OUTPUT_DETAIL [Text]
 
Description:  With the sensible default of NONE no additional information is produced. With any other value, regardless of what it is, relevant solvation data, such as densities, potentials, dielectric permittivities, gradient terms are produced in 3D grid formats (cube, dx, grd  depending on CUBE_FORMAT , DX_FORMAT and GRD_FORMAT ) in every step. These consume a lot of disk space and should only be used for debugging.  
Default Value: 
 
Example: 
IS_SOLVATION_OUTPUT_DETAIL SOME  
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Syntax:  IS_SOLVENT_SURFACE_TENSION [Value] [Unit]  
Description:  Sets the surface tension of the solvent. This is only relevant in implicit solvent calculations.
 
Default Value: 
 
Example: 
IS_SOLVENT_SURFACE_TENSION 1.33859E5 ha/bohr**2 ; corresponds to H2O with approximate inclusion of dispersionrepulsion  
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Syntax:  IS_SOLVENT_SURF_TENSION [Value] [Unit]  
Description:  Sets the surface tension of the solvent. This is only relevant in implicit solvent calculations.
 
Default Value: 
 
Example: 
IS_SOLVENT_SURF_TENSION 4.7624E5 ha/bohr**2 ; suitable for H2O, corresponds to 0.07415 N/m  
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Syntax:  is_steric_write [Boolean]  
Description:  Specifies whether the steric potential (used in implicit solvation with Boltzmann ions) is to be written to a (dx/cube/grd) file.  
Default Value: 
 
Example: 
is_steric_write T  
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Syntax:  IS_SURFACE_THICKNESS [Value]
 
Description:  Sets the electronic isosurface thickness (in atomic units of charge density) used to calculate the surface area of the dielectric cavity. This is only relevant in implicit solvent calculations.  
Default Value: 
 
Example: 
IS_SURFACE_THICKNESS 0.0003  
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Syntax:  KERNEL_CHRISTOFFEL_UPDATE [Logical]  
Description:  Preserve the densitymatrix (idempotency, norm) to first order when the NGWFs change. Only implemented for zerotemperature groundstate calculations.  
Default Value: 
 
Example: 
kernel_christoffel_update T  
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Syntax:  KERNEL_CUTOFF [Value] [Unit]  
Description:  Specifies the density kernel spatial cutoff. Matrix elements are only included if the corresponding NGWF centres are closer than this distance.
 
Default Value: 
 
Example: 
kernel_cutoff 25.0 bohr  
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Syntax:  KERNEL_DIIS_COEFF [Real]
 
Description:  Fraction of the output density kernel or Hamiltonian matrix in the inner loop DIIS. Its value must be in the range [0,1]. Set to a negative number to enable the ODA method for calculating the optimum mixing parameter. References: E. Cancès, and C. Le Bris, Int. J. Quantum Chem. 79(2):82, 2000. E. Cancès, J. Chem. Phys. 114(24):10616, 2001.  
Default Value: 
 
Example: 
kernel_diis_coeff 0.2500  
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Syntax:  KERNEL_DIIS_CRITERIA [Text]  
Description:  Set convergence criteria for inner loop diis. This input flag acts as a logical switch whose terms can only have the values 0 for false and 1 for true. Written as kernel_diis_criteria = wxyz, each component refers to:
w : residual: sqrt[sum(K_{out}  K_{in})^2] Two or more elements activated means that the two criteria have to be true at the same time to achieve convergence (i.e. they have to be lower than kernel_diis_threshold).
 
Default Value: 
 
Example: 
kernel_diis_conv_criteria 0110 (activates x and y but not w or z)  
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Syntax:  KERNEL_DIIS_LINEAR_ITER [Integer]
 
Description:  Set the number of linear mixing iterations before activating Pulay, LiSTi or LiSTb mixing. The aim of these iterations is to generate a history of accurate density kernels to be used with the Pulay, LiSTi or LiSTb methods.  
Default Value: 
 
Example: 
kernel_diis_linear_iter 10  
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Syntax:  KERNEL_DIIS_LSHIFT [Value] [Units]  
Description:  Value of the shift in energy of the conduction bands with the levelshifting technique during the inner loop DIIS. Reference:
V. R. Saunders, and I. H. Hillier, Int. J. Quantum Chem. 7(4):699, 1973.
 
Default Value: 
 
Example: 
kernel_diis_lshift: 1 eV  
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Syntax:  KERNEL_DIIS_LS_ITER [Integer]
 
Description:  Number of iterations of the inner loop DIIS method with levelshifting enabled.  
Default Value: 
 
Example: 
kernel_diis_ls_iter: 5  
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Syntax:  KERNEL_DIIS_MAXIT [Integer]
 
Description:  Maximum number of inner loop DIIS iterations  
Default Value: 
 
Example: 
kernel_diis_maxit 40  
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Syntax:  KERNEL_DIIS_SCHEME [Text]
 
Description:  Enable selfconsistent density kernel or Hamiltonian mixing during the inner loop. Possible options:
References: P. Pulay, Chem. Phys. Lett. 73(2):393, 1980. Y. A. Wang, C. Y. Yam, Y. K. Chen, and G. Chen, J. Chem. Phys. 134(24):241103, 2011 Y. K. Chen, and Y. A. Wang, J. Chem. Theory Comput. 7(10):3045, 2011.  
Default Value: 
 
Example: 
kernel_diis_scheme DKN_PULAY  
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Syntax:  KERNEL_DIIS_SIZE [Integer]
 
Description:  Maximum number of density kernel or Hamiltonian matrices that will be stored in memory. These kernels are then used with the Pulay, LiSTi or LiSTb schemes to generate the next input matrix. Warning: the more matrices are stored, the better the convergence will be, but also the more memory resources will be needed.  
Default Value: 
 
Example: 
kernel_diis_size 25  
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Syntax:  KERNEL_DIIS_THRESHOLD [Real]  
Description:  Convergence threshold for the inner loop selfconsistent optimisation. It acts for all active values of kernel_diis_conv_criteria.
 
Default Value: 
 
Example: 
kernel_diis_thres 1.0e7  
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Syntax:  KERNEL_UPDATE [Logical]
 
Description:  Update the density kernel when taking a trial step for NGWF optimization.  
Default Value: 
 
Example: 
kernel_update T  
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Syntax:  KE_DENSITY_CALCULATE [Logical]  
Description:  Calculate kinetic energy density.  
Default Value: 
 
Example: 
ke_density_calculate T  
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Syntax:  K_ZERO [Value] [Unit]  
Description:  Specifies the kinetic energy preconditioning parameter. See Mostofi et al.,J. Chem. Phys.119, 8842 (2003) for further details.
 
Default Value: 
 
Example: 
k_zero 4.0 bohr  
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Syntax: 
 
Description:  Specifies the lattice vectors a1, a2 and a3 for the simulation cell as Cartesian coordinates. By default, these will be interpreted as being in atomic units (a0), but they will be interpreted as being Angstroms if "ang" is on the first line of the block.  
Default Value:  
Example: 
 
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Syntax:  LIBXC_C_FUNC_ID [Integer]
 
Description:  Functional ID for the correlation functional (used in calculations employing the LIBXC library). The value of FUNCTIONAL must be set to LIBXC for this value to be accessed  
Default Value: 
 
Example: 
libxc_c_func_id 13  
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Syntax:  LIBXC_X_FUNC_ID [Integer]
 
Description:  Functional ID for the exchange functional (used in calculations employing the LIBXC library). The value of FUNCTIONAL must be set to LIBXC for this value to be accessed  
Default Value: 
 
Example: 
libxc_x_func_id 13  
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Syntax:  LNV_CG_MAX_STEP [Value]  
Description:  Maximum length of trial step for kernel optimisation line search
 
Default Value: 
 
Example: 
lnv_cg_max_step 10.0  
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Syntax:  LNV_CG_TYPE [Text]
 
Description:  Specifies the variant of the conjugate gradients algorithm used for the optimization of the density kernel, currently either LNV_FLETCHER for FletcherReeves or LNV_POLAK for PolakRibiere.  
Default Value: 
 
Example: 
lnv_cg_type LNV_POLAK  
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Syntax:  LNV_CHECK_TRIAL_STEPS [Logical]  
Description:  Activate checks on the stability of kernel at each trial step during LNV line search. Checks occupancy bounds and RMS occupancy error
 
Default Value: 
 
Example: 
lnv_check_trial_steps T  
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Syntax:  LNV_THRESHOLD_ORIG [Real]  
Description:  Specifies the convergence threshold for the RMS gradient of the density kernel.
 
Default Value: 
 
Example: 
lnv_threshold_orig 1.0e8  
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Syntax:  LOCPOT_SCHEME [Text]
 
Description:  Scheme for evaluating local potential matrix elements. Possible values: FULL = Calculate matrix and symmetrize explicitly; LOWER = Calculate lower triangle elements only and infer upper triangle; ALTERNATE = Calculate alternating elements from both triangles and expand (fastest).  
Default Value: 
 
Example: 
locpot_scheme ALTERNATE  
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Syntax:  LR_TDDFT_ANALYSIS [Logical]  
Description:  If the flag is set to True, a full cubicscalling analysis of each TDDFT excitation is performed in which the response density is decomposed into dominant KohnSham transitions.  
Default Value: 
 
Example: 
lr_tddft_analysis True  
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Syntax:  LR_TDDFT_CG_THRESHOLD [Real]  
Description:  The keyword specifies the convergence tolerance on the sum of the n TDDFT excitation energies. If the sum of excitation energies changes by less than LR_TDDFT_CG_THRESHOLD in two consecutive iterations, the calculation is taken to be converged.  
Default Value: 
 
Example: 
lr_tddft_cg_threshold 5.0E7  
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Syntax:  LR_TDDFT_JOINT_SET [Logical]  
Description:  If the flag is set to T, the joint NGWF set is used to represent the conduction space in the LRTDDFT calculation.  
Default Value: 
 
Example: 
lr_tddft_joint_set False  
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Syntax:  LR_TDDFT_KERNEL_CUTOFF [Value] [Unit]  
Description:  Keyword sets a truncation radius on all response density kernels in order to
achieve linear scaling computational effort with system size.  
Default Value: 
 
Example: 
lr_tddft_kernel_cutoff 30.0 bohr  
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Syntax:  LR_TDDFT_MAXIT_CG [Integer]  
Description:  The maximum number of conjugate gradient iterations the algorithm will perform.  
Default Value: 
 
Example: 
lr_tddft_maxit_cg 100  
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Syntax:  LR_TDDFT_MAXIT_PEN [Integer]  
Description:  The maximum number purification iterations performed per conjugate gradient step.  
Default Value: 
 
Example: 
lr_tddft_maxit_pen 50  
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Syntax:  LR_TDDFT_NUM_STATES [Integer]  
Description:  The keyword specifies how many excitations we want to converge. If set to a positive integer n, the TDDFT algorithm will converge the n lowest excitations of the system.  
Default Value: 
 
Example: 
lr_tddft_num_states 10  
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Syntax:  LR_TDDFT_PENALTY_TOL [Real]  
Description:  Keyword sets a tolerance for the penalty functional. If the penalty functional is larger than LR_TDDFT_PENALTY_TOL, the algorithm will perform purification iterations in order to decrease the penalty value and force towards the correct idempotency behaviour.  
Default Value: 
 
Example: 
lr_tddft_penalty_tol 5.0E9  
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Syntax:  LR_TDDFT_PROJECTOR [Logical]  
Description:  If the flag is set to True, the conduction density matrix is redefined to be a projector onto the entire unoccupied subspace.  
Default Value: 
 
Example: 
lr_tddft_projector False  
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Syntax:  LR_TDDFT_RESTART [Logical]  
Description:  If the flag is set to True, the algorithm reads in LR_TDDFT_NUM_STATES response density kernels in .dkn format and uses them as initial trial vectors for a restarted LRTDDFT calculation.  
Default Value: 
 
Example: 
lr_tddft_restart True  
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Syntax:  LR_TDDFT_RPA [Logical]  
Description:  If the flag is set to True, a full TDDFT calculation in the socalled "Random Phase Approximation" will be performed, rather than invoking the TammDancoff approximation  
Default Value: 
 
Example: 
lr_tddft_rpa True  
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Syntax:  LR_TDDFT_TRIPLET [Logical]  
Description:  Flag that decides whether the LR_TDDFT_NUM_STATES states to be converged are singlet or triplet states.  
Default Value: 
 
Example: 
lt_tddft_triplet T  
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Syntax:  LR_TDDFT_WRITE_DENSITIES [Logical]  
Description:  If the flag is set to True, the response density, electron density and hole density
for each excitation is computed and written into a .cube file.  
Default Value: 
 
Example: 
lr_tddft_write_densities False  
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Syntax:  LR_TDDFT_WRITE_KERNELS [Logical]  
Description:  If the flag is set to T, the TDDFT response density kernels are printed out at every conjugate gradient iteration. These files are necessary to restart a LRTDDFT calculation.  
Default Value: 
 
Example: 
lr_tddft_write_kernels False  
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Syntax:  LUMO_DENS_PLOT [Integer]  
Description:  Specifies the number of canonical orbitals above the LUMO to plot, if DO_PROPERTIES is set to true. Thus a value of zero plots only the LUMO, a negative value disables plotting and a positive value of N plots the N+1 lowest unoccupied canonical orbitals.
 
Default Value: 
 
Example: 
lumo_dens_plot 0  
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Syntax:  LUMO_PLOT [Integer]
 
Description:  Specifies the number of canonical orbitals above the LUMO to plot, if DO_PROPERTIES is set to true. Thus a value of zero plots only the LUMO, a negative value disables plotting and a positive value of N plots the N+1 lowest unoccupied canonical orbitals.  
Default Value: 
 
Example: 
lumo_plot 0  
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Syntax:  MAXIT_CDFT_U_CG [Integer]  
Description:  Specifies the maximum number of iterations for the constraining potentials (Uq/s) conjugate gradients optimisation.  
Default Value: 
 
Example: 
maxit_cdft_u_cg 1  
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Syntax:  MAXIT_HOTELLING [Integer]
 
Description:  Specifies the maximum number of iterations in the Hotelling algorithm used to invert the overlap matrix. See Ozaki,Phys. Rev. B.64, 195110 (2001) for more details. If MAXIT_HOTELLING is zero, then the inverse is computed using a traditional O(N^3) method.  
Default Value: 
 
Example: 
maxit_hotelling 100  
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Syntax:  MAXIT_LNV [Integer]  
Description:  Specifies the maximum number of iterations for the density kernel optimization.
 
Default Value: 
 
Example: 
maxit_lnv 3  
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Syntax:  MAXIT_NGWF_CG [Integer]  
Description:  Specifies the maximum number of iterations for the NGWF conjugate gradients optimization.
 
Default Value: 
 
Example: 
maxit_ngwf_cg 25  
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Syntax:  MAXIT_PALSER_MANO [Integer]
 
Description:  Specifies the maximum number of iterations for the PalserManolopoulos algorithm [Phys. Rev. B.58, 12704 (1998)] used to initialize the density kernel before the main optimization begins (when COREHAM_DENSKERN_GUESS is true, the default). If MAXIT_PALSER_MANO is negative then a traditionalO(N3) diagonalization is used.  
Default Value: 
 
Example: 
maxit_palser_mano 30  
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Syntax:  MAXIT_PEN [Integer]  
Description:  Specifies the maximum number of iterations for the penaltyfunctional algorithm [ Hayneset al.,Phys. Rev. B.59, 12173 (1999) ] used to refine the density kernel intialization before the main optimization begins. When reading the density kernel from disk this should normally be set to zero.
 
Default Value: 
 
Example: 
maxit_pen 5  
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Syntax:  MAX_RESID_HOTELLING [Real]  
Description:  Specifies the maximum residual allowed when inverting the overlap matrix by the Hotelling method. See Ozaki,Phys. Rev. B.64, 195110 (2001) for more details.
 
Default Value: 
 
Example: 
max_resid_hotelling 1.0e10  
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Syntax:  MD_DELTA_T [Value] [Unit]
 
Description:  Specifies the time step for molecular dynamics.  
Default Value: 
 
Example: 
md_delta_t 1.0 fs  
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Syntax:  MD_NUM_ITER [Integer]
 
Description:  Specifies the number of molecular dynamics steps.  
Default Value: 
 
Example: 
md_num_iter 1000  
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Syntax:  MD_RESET_HISTORY [Integer]  
Description:  By default, in a molecular dynamics calculation, the initial guess for the electronic degrees of freedom is provided by the optimized NGWFs and density kernel from the previous time step. MD_RESET_HISTORY specifies the number of MD steps to be performed before the generation of new initial guesses for the NGWFs and density kernel. See MIX_DKN_TYPE and MIX_NGWFS_TYPE for more advanced mixing options.
 
Default Value: 
 
Example: 
md_reset_history 1000  
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Syntax:  MD_RESTART [Logical]
 
Description:  Restart the molecular dynamics calculation from previously generated backup files (i.e. *.md.restart and *.thermo.restart files).  
Default Value: 
 
Example: 
md_restart T  
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Syntax:  MG_DEFCO_FD_ORDER [Integer]  
Description:  Order of finite differences to use in the highorder defect correction component of the multigrid solver. MG_DEFCO_FD_ORDER must be positive and even  
Default Value: 
 
Example: 
mg_defco_fd_order 3  
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Syntax:  MG_GRANULARITY_POWER [Integer]  
Description:  Power of 2 which gives multigrid granularity, i.e. granularity = 2**N where N is MG_GRANULARITY_POWER. MG_GRANULARITY_POWER must be > 0.  
Default Value: 
 
Example: 
mg_granularity_power 5  
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Syntax:  MG_TOL_RES_REL  
Description:  Relative tolerance in norm of residual for defect correction procedure in multigrid solver. MG_TOL_RES_REL must be >= 0.0.  
Default Value: 
 
Example: 
mg_tol_res_rel 1.0e1  
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Syntax:  MINIT_LNV [Integer]  
Description:  Specifies the minimum number of iterations for the density kernel optimization.
 
Default Value: 
 
Example: 
minit_lnv 1  
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Syntax:  MIX_DKN_INIT_NUM [Integer]  
Description:  Length of the initialization phase for the density kernel. Number of MD steps before the activation of the extrapolation/propagation scheme for building density kernel initial guesses.  
Default Value: 
 
Example: 
mix_dkn_init_num 2  
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Syntax:  MIX_DKN_INIT_TYPE [Text]  
Description:  Specifies the mixing scheme used during the initialisation phase for the density kernel.
 
Default Value: 
 
Example: 
mix_dkn_init_type REUSE  
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Syntax:  MIX_DKN_NUM [Integer]  
Description:  Number of density kernels required by the density kernel mixing scheme in order to generate the new initial guesses for the density kernel SCF process. See MIX_DKN_TYPE for a description of the available mixing schemes. The default depends on MIX_DKN_TYPE .
 
Default Value: 
 
Example: 
mix_dkn_num 2  
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Syntax:  MIX_DKN_RESET [Integer]  
Description:  MIX_DKN_RESET specifies the number of MD steps to be performed before the generation of a new initial guess for the density kernel. See MIX_DKN_TYPE for more advanced mixing options.  
Default Value: 
 
Example: 
mix_dkn_reset 100  
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Syntax:  MIX_DKN_TYPE [Text]  
Description:  Specifies the mixing scheme used to generate new initial guesses for the density kernel from the density kernels optimized at previous MD steps.
 
Default Value: 
 
Example: 
mix_dkn_type REUSE  
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Syntax:  MIX_LOCAL_LENGTH [Value] [Unit]  
Description:  Specifies the localization length required by MIX_NGWFS_TYPE =3.
 
Default Value: 
 
Example: 
mix_local_length 15.0 bohr  
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Syntax:  MIX_LOCAL_SMEAR [Value] [Unit]  
Description:  Allows to smear out the localization sphere used when MIX_NGWFS_TYPE =3.
 
Default Value: 
 
Example: 
mix_local_length 3.0 bohr  
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Syntax:  MIX_NGWFS_INIT_NUM [Integer]  
Description:  Length of the initialization phase for NGWFs. Number of MD steps before the activation of the extrapolation/propagation scheme for building density kernel initial guesses.  
Default Value: 
 
Example: 
mix_ngwfs_init_num 2  
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Syntax:  MIX_NGWFS_INIT_TYPE [Text]  
Description:  Specifies the mixing scheme used during the initialisation phase for the NGWFs.
 
Default Value: 
 
Example: 
mix_ngwfs_init_type REUSE  
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Syntax:  MIX_NGWFS_NUM [Integer]  
Description:  Number of NGWFs sets required by the NGWFs mixing scheme in order to generate the new initial guesses for the NGWFs optimization process. See MIX_NGWFS_TYPE for a description of the available mixing schemes. Default depends on MIX_NGWFS_TYPE .
 
Default Value: 
 
Example: 
mix_ngwfs_num 2  
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Syntax:  MIX_NGWFS_RESET [Integer]  
Description:  MIX_NGWFS_RESET specifies the number of MD steps to be performed before the generation of new initial guesses for the NGWFs. See MIX_NGWFS_TYPE for more advanced mixing options.  
Default Value: 
 
Example: 
mix_ngwfs_reset 100  
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Syntax:  MIX_NGWFS_TYPE [Text]  
Description:  Specifies the mixing scheme used to generate new initial guesses for the NGWFs from the NGWFs optimized at previous MD steps.
 
Default Value: 
 
Example: 
mix_ngwfs_type REUSE  
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Syntax:  NBO_AOPNAO_SCHEME [Text]  
Description:  Thee AO to PNAO scheme to use. Affects the lmaveraging and diagonalisation steps in the initial AO to PNAO, NRB lmaveraging, and rediagonalisation transformations. For testing purposes only  so far none of the other schemes apart from ORIGINAL works. Possbile values are:
 
Default Value: 
 
Example: 
nbo_aopnao_scheme DIAGONALIZATION  
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Syntax:  NBO_INIT_LCLOWDIN [Logical]  
Description:  Performs atomlocal Lowdin orthogonalisation on NGWFs as the first step before constructing NAOs.  
Default Value: 
 
Example: 
nbo_init_lclowdin T  
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Syntax: 
 
Description:  The list of NBO_PLOT_ORBTYPE orbitals to be plotted, identified by their indices as in the gennbo output. Specify each index on a new line.  
Default Value:  
Example: 
GENNBO output indices specified on separate lines:
%block nbo_list_plotnbo  
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Syntax:  NBO_PLOT_ORBTYPE [Text]  
Description:  The type of gennbogenerated orbitals to read and plot. Possible values and their associated gennbo
transformation files must be present, as follows: NBO_PLOT_ORBTYPE causes the nonorthogonalised PNAOs to be used in plotting instead of NAOs. PNAOs are of the normal type, i.e. when RPNAO = F in gennbo (default).  
Default Value:  
Example: 
nbo_plot_orbtype NAO  
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Syntax:  NBO_PNAO_ANALYSIS [Logical]  
Description:  Perform s/p/d/f analysis on the PNAOs (analogous to NGWF_ANALYSIS ).
 
Default Value: 
 
Example: 
nbo_pnao_analysis T  
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Syntax:  NBO_SCALE_DM [Logical]  
Description:  Scales partial density matrix output to seedname_nao_nbo.47 in order to achieve charge integrality.  
Default Value: 
 
Example: 
nbo_scale_dm F  
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Syntax:  NBO_SCALE_SPIN [Logical]  
Description:  Scales alpha and beta spins independently to integral charge when partial matrices are printed and NBO_SCALE_DM = T. Inevitably means spin density values from gennbo are invalid and one should calculate them manually from the NPA populations.  
Default Value: 
 
Example: 
nbo_scale_spin F  
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Syntax: 
 
Description:  Optional userdefined (false) lmlabel for NGWFs according to gennbo convention. "N" suffix denotes NMB orbital. If "SOLVE" orbitals are used, this block should be present, as "AUTO" initialisation assumes orbitals were also initialised as "AUTO".  
Default Value: 
 
Example: 
Species not specified will default to AUTO:
%block nbo_species_ngwflabel  
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Syntax:  NBO_WRITE_DIPOLE [Logical]  
Description:  Computes and writes dipole matrix to FILE.47  
Default Value: 
 
Example: 
nbo_write_dipole T  
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Syntax:  NBO_WRITE_LCLOWDIN [Logical]  
Description:  Writes full matrices (all atoms) in the atomlocal Lowdinorthogonalized basis to FILE.47 (For reference/testing/comparison purposes). Output will be seedname_lclowdin_nbo.47  
Default Value: 
 
Example: 
nbo_write_lclowdin T  
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Syntax:  NBO_WRITE_NPACOMP [Logical]  
Description:  Writes NAO charges for all orbitals to standard output.  
Default Value: 
 
Example: 
nbo_write_npacomp T  
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Syntax: 
 
Description:  Block of lists of species to be included in the partial matrix output of seedname_nao_nbo.47. If not
present all atoms will be included.  
Default Value:  
Example: 
If specified will default to AUTO:
%block nbo_write_species  
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Syntax:  NEB_CI_DELAY [Integer]  
Description:  Defines the number of BFGS steps the chain should take before enabling a climbing image. Negative numbers disable the climbing image entirely.  
Default Value: 
 
Example: 
neb_ci_delay 5  
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Description:  Continue NEB run from .neb_cont files. 
Default Value: 

Example:  NEB_CONTINUATION T 
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Syntax:  NEB_PRINT_SUMMARY [Boolean]  
Description:  If True, ONETEP will print NEB convergence information as well as a summary of the reduced reaction coordinate and relative energy of each bead after each NEB step to the original stdout.  
Default Value: 
 
Example: 
neb_print_summary F  
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Syntax:  NGWF_CG_MAX_STEP [Value]  
Description:  Maximum length of trial step for NGWF optimisation line search. If NGWFS_CG_MAX_STEP is set to be negative, then NGWFS_CG_MAX_STEP = NGWFS_CG_MAX_STEP * (CUTOFF_ENERGY / 22.04959837). For positive values, it is left unchanged.
 
Default Value: 
 
Example: 
ngwf_cg_max_step 10.0  
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Syntax:  NGWF_CG_ROTATE [Logical]  
Description:  Rotate the density kernel to the new NGWF representation after CG update. In EDFT calculations, it also rotates the eigenvectors.
 
Default Value: 
 
Example: 
ngwf_cg_rotate T  
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Syntax:  NGWF_CG_TYPE [Text]
 
Description:  Specifies the variant of the conjugate gradients algorithm used for the optimization of the NGWFs, currently either NGWF_FLETCHER for FletcherReeves or NGWF_POLAK for PolakRibiere.  
Default Value: 
 
Example: 
ngwf_cg_type NGWF_POLAK  
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Syntax:  NGWF_HALO [Real]
 
Description:  Specifies a halo size for the NGWFs to include matrix elements between NGWFs which do not directly overlap. In atomic units (a0). A negative value indicates that no halo should be used.  
Default Value: 
 
Example: 
ngwf_halo 1.0  
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Syntax:  NGWF_MAX_GRAD [Real]  
Description:  Specifies the convergence threshold for the maximum value of the NGWF gradient at any psinc grid point. Ignored if negative.
 
Default Value: 
 
Example: 
ngwf_max_grad 1.0e4  
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Syntax:  NGWF_THRESHOLD_ORIG [Real]  
Description:  Specifies the convergence threshold for the RMS gradient of the NGWFs.
 
Default Value: 
 
Example: 
ngwf_threshold_orig 1.0e5  
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Syntax:  NNHO [Logical]  
Description:  Generate nonorthogonal natural hybrid orbitals from the NGWFs. See Fosteret al.,J. Am. Chem. Soc.102, 7211 (1980) for more details.
 
Default Value: 
 
Example: 
nnho T  
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Syntax:  NONSC_FORCES [Logical]  
Description:  Calculates the residual non selfconsistent forces due to the NGWF gradient.
 
Default Value: 
 
Example: 
nonsc_forces true  
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Syntax:  NUM_EIGENVALUES [Integer]
 
Description:  Specifies the number of canonical orbital eigenvalues above and below the Fermi level to print when properties are required.  
Default Value: 
 
Example: 
num_eigenvalues 5  
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Syntax:  NUM_IMAGES [Integer]  
Description:  Defines the number of ONETEP instances that should run in parallel in the simulation and enables imageparallel mode. ONETEP must be run with MPI and the number of MPI processes must be divisible by the number of ONETEP images unless advanced specification is used. (see: image_sizes)
In NEB, this is also the number of beads in the chain.  
Default Value: 
 
Example: 
num_images 5  
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Syntax:  OCC_MIX [Real]
 
Description:  Specifies the fraction of the NGWF gradient to which occupancy preconditioning is applied.  
Default Value: 
 
Example: 
occ_mix 1.0 ; fully preconditioned gradient  
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Syntax:  ODD_PSINC_GRID [Logical]
 
Description:  Forces the simulation cell psinc grid to contain an odd number of points in each direction.  
Default Value: 
 
Example: 
odd_osinc_grid T  
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Syntax:  OLD_LNV [Logical]
 
Description:  Enables backwards compatibility with legacy code.  
Default Value: 
 
Example: 
old_lnv T  
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Syntax:  OPENBC_HARTREE [Logical]  
Description:  Forces open boundary conditions in the calculation of the Hartree energy. These are automatically used whenever smeared ions (IS_SMEARED_ION_REP ) are in use. This keyword can be used to force them in other (extremely rare) situations. It cannot be used to force them off.
 
Default Value: 
 
Example: 
OPENBC_HARTREE T  
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Syntax:  OPENBC_ION ION [Logical]  
Description:  Forces open boundary conditions in the calculation of the ionion energy. These are automatically used whenever MartynaTuckerman (PBC_CORRECTION_CUTOFF ), cutoff Coulomb (COULOMB_CUTOFF_TYPE ) or smeared ions (IS_SMEARED_ION_REP ) are in use. This keyword can be used to force them in other (extremely rare) situations. It cannot be used to force them off.
 
Default Value: 
 
Example: 
OPENBC_ION_ION T  
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Syntax:  OPENBC_PSPOT [Logical]  
Description:  Forces open boundary conditions in the calculation of the local pseudopotential energy. These are automatically used whenever smeared ions (IS_SMEARED_ION_REP ) are in use. This keyword can be used to force them in other (extremely rare) situations. It cannot be used to force them off.
 
Default Value: 
 
Example: 
OPENBC_PSPOT T  
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Syntax:  OPENBC_PSPOT_FINETUNE_ALPHA [Value]
 
Description:  Sets the value of a numerical parameter (alpha) used in the calculation of the local pseudopotential in open boundary conditions. This parameter controls the transition between the shortrange and longrange parts of the pseudopotential. Its impact on the total energy is negligible, provided it stays within reasonable bounds. Units of 1/bohr are implicitly assumed. This keyword is only relevant for calculations with open boundary conditions.  
Default Value: 
 
Example: 
OPENBC_PSPOT_FINETUNE_ALPHA 0.5  
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Syntax:  OPENBC_PSPOT_FINETUNE_F [INTEGER]
 
Description:  Sets the value of a unitless numerical parameter (grid fineness factor, f ) used in the calculation of the local pseudopotential in open boundary conditions. This parameter controls the fineness of the reciprocal space radial grid used in the calculation. Its impact on the total energy is negligible, provided it stays within reasonable bounds. The default value of 1 causes f to be determined automatically  this will generate a 'safe' value, making the grid as fine as necessary to have at least 50 sample gpoints in any period of sin(gx) for the largest x in use in the calculation (the diagonal of the simulation cell). Thus, the automatically generated value depends on the cell size. Increasing this value makes little sense. Decreasing this value allows calculations to start faster, but decreases accuracy. This keyword is only relevant for calculations with open boundary conditions.  
Default Value: 
 
Example: 
OPENBC_PSPOT_FINETUNE_F 6  
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Syntax:  OPENBC_PSPOT_FINETUNE_NPTS_X [INTEGER]
 
Description:  Sets the value of a unitless numerical parameter npts_x used in the calculation of the local pseudopotential in open boundary conditions. This parameter controls the number of points in the radial realspace grid on which the local pseudopotential is evaluated before interpolation to the 3D grid takes place. Increasing this value will offer marginal increase in accuracy at the expense of calculation wall time. This keyword is only relevant for calculations with open boundary conditions.  
Default Value: 
 
Example: 
OPENBC_PSPOT_FINETUNE_NPTS_X 500000  
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Syntax:  OUTPUT_DETAIL [Text]
 
Description:  Specifies the level of detail in ONETEP's output: either BRIEF , NORMAL or VERBOSE .  
Default Value: 
 
Example: 
output_detail VERBOSE  
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Syntax:  OVLP_FOR_NONLOCAL [Logical]
 
Description:  Forces the nonlocal pseudopotential matrix and hence the Hamiltonian to have the sparsity pattern of the overlap matrix.  
Default Value: 
 
Example: 
ovlp_for_nonlocal T  
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Syntax: 
 
Description:  Cutoff Coulomb only. Specifies the padded lattice vectors a1, a2 and a3 for the 'padded' simulation cell as Cartesian coordinates. By default, these will be interpreted as being in atomic units (a0), but they will be interpreted as being Angstroms if "ang" is on the first line of the block.  
Default Value:  
Example: 
 
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Syntax:  PAW [Logical]
 
Description:  Activates the Projector Augmented Wave Formalism: PAW potentials must then be supplied in the species_pot block.  
Default Value: 
 
Example: 
PAW : T  
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Syntax:  PBC_CORRECTION_CUTOFF [Value] [Unit]  
Description:  Turns on the MartynaTuckerman correction to the effects of periodic boundary conditions (PBCs), specifies the dimensionless cutoff parameter. A value of 7.0 is recommended by the authors in Martyna GJ and Tuckerman ME, J. Chem. Phys. 110, 2810 (1999), DOI:10.1063/1.477923.
 
Default Value: 
 
Example: 
pbc_correction_cutoff 7.0 bohr  
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Syntax:  PEN_PARAM [Real]
 
Description:  Specifies the energy parameter in hartrees for the penaltyfunctional algorithm [ Hayneset al.,Phys. Rev. B.59, 12173 (1999) ] used to refine the density kernel intialization before the main optimization begins.  
Default Value: 
 
Example: 
pen_param 5.0  
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Syntax: 
 
Description:  List of Gammapoint modes (where 1 is the lowest) for which to write xyz animation files.  
Default Value: 
 
Example: 
%block phonon_animate_list  
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Syntax:  PHONON_ANIMATE_SCALE [Real]  
Description:  Relative scale of the amplitude of the vibration in the xyz animation.  
Default Value: 
 
Example:  phonon_animate_scale 2.0  
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Syntax:  PHONON_DELTAT [Value] [Unit]  
Description:  Temperature step for the computation of thermodynamic quantities.  
Default Value: 
 
Example:  phonon_deltat 0.5E5 Ha  
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Syntax: 
 
Description:  List of force constant calculations to perform for Stage 2 in phonon calculations (i.e. in the case of phonon_farming_task 2 or 0). Note that the total number of force constant calculations is given in the main output file in the line 'Number of force constants'; this will be less than or equal to 3N. The numbers listed in the phonon_disp_list block should go from 1 to this number; they can only be equated to the label 'i' if all 3N force constants are calculated. If unspecified, all displacements are performed.  
Default Value: 
 
Example: 
%block phonon_disp_list  
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Syntax:  PHONON_DOS [Logical]  
Description:  Calculate the phonon DOS and write to file.  
Default Value: 
 
Example:  phonon_dos F  
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Syntax:  PHONON_DOS_DELTA [Real]  
Description:  Frequency step for the phonon DOS calculation (in 1/cm).  
Default Value: 
 
Example:  phonon_dos_delta 5.0  
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Syntax:  PHONON_DOS_MAX [Real]  
Description:  Upper bound of the phonon DOS range (in 1/cm).  
Default Value: 
 
Example:  phonon_dos_max 1500.0  
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Syntax:  PHONON_DOS_MIN [Real]  
Description:  Lower bound of the phonon DOS range (in 1/cm).  
Default Value: 
 
Example:  phonon_dos_min 2.0  
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Syntax:  PHONON_ENERGY_CHECK [Logical]  
Description:  Perform a sanity check that the total energy does not decrease upon ionic displacement.  
Default Value: 
 
Example:  phonon_energy_check T  
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Syntax: 
 
Description:  This is a block in which the user can list specific ioncoordinate pairs with options differing from the global defaults defined by PHONON_VIB_FREE , PHONON_SAMPLING , and PHONON_FINITE_DISP .  
Default Value: 
 
Example: 
In this example, we are overwriting the default %block phonon_exception_list  
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Syntax:  PHONON_FARMING_TASK [Integer]  
Description:  The most efficient way of performing a phonon calculation is by task farming, as the full force constants matrix is built up from many perturbedstructure calculations, each of which is completely independent. This can be done with the following steps:
 
Default Value: 
 
Example:  phonon_farming_task 1  
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Syntax:  PHONON_FINITE_DISP [VALUE] [Unit]  
Description:  Ionic displacement distance used in the finitedifference formula.  
Default Value: 
 
Example:  phonon_finite_disp 5.0E2 bohr  
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Syntax:  PHONON_FMAX [Value] [Unit]  
Description:  Maximum ionic force allowed in the unperturbed system.  
Default Value: 
 
Example:  phonon_fmax 2.5E3 'ha/bohr'  
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Syntax: 
 
Description:  Definition of the regular grid of qpoints used in phonon calculations for the computation of thermodynamic quantities and the phonon DOS. Default is 1 1 1 (i.e. Gamma point only).  
Default Value: 
 
Example: 
In this example, we define a 10x10x10 sampling grid (over b1, b2 and b3 respectively), instead of the 1x1x1 default grid.
%block phonon_grid  
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Syntax:  PHONON_MIN_FREQ [Value] [Unit]  
Description:  Minimum phonon frequency for the computation of thermodynamic quantities, expressed as an energy; frequencies lower than this are discarded.  
Default Value: 
 
Example:  phonon_min_freq 2.0E6 Ha  
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Syntax: 
 
Description:  List of additional qpoints for which to calculate the phonon frequencies, in fractional coordinates of the reciprocal unit cell vectors. For nonsupercell calculations only the Gamma point can be specified.  
Default Value: 
 
Example: 
%block phonon_qpoints  
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Syntax:  PHONON_SAMPLING [Integer]  
Description:  Selects which finitedifference formula to use. The elements of the force constants matrix are calculated by a centraldifference formula, using either 2 (the default phonon_sampling 1) or 4 displacements (phonon_sampling 2). See documentation file for more information.  
Default Value: 
 
Example:  phonon_sampling 2  
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Syntax:  PHONON_SK [Logical]  
Description:  Use a SlaterKoster style interpolation for qpoints instead of a realspace cutoff of the force constants matrix elements.  
Default Value: 
 
Example:  phonon_sk T  
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Syntax:  PHONON_TMAX [Value] [Unit]  
Description:  Upper bound of the temperature range for the computation of thermodynamic quantities.  
Default Value: 
 
Example:  phonon_tmax 3.0E3 Ha  
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Syntax:  PHONON_TMIN [Value] [Unit]  
Description:  Lower bound of the temperature range for the computation of thermodynamic quantities, expressed as an energy (k_B T).  
Default Value: 
 
Example:  phonon_tmin 0.001 Ha  
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Syntax:  PHONON_VIB_FREE [Integer]  
Description:  This integer parameter controls the global default of which Cartesian directions are switched on for all ions. The options are: 0 (x=F y=F z=F), 1 (x=T y=F z=F), 2 (x=F y=T z=F), 3 (x=T y=T z=F), 4 (x=F y=F z=T), 5 (x=T y=F z=T), 6 (x=F y=T z=T) and 7 (x=T y=T z=T). The values in parenthesis explain which Cartesian direction (i.e. vibrational degree of freedom) is allowed.  
Default Value: 
 
Example:  phonon_vib_free 9  
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Syntax:  PHONON_WRITE_EIGENVECS [Logical]  
Description:  Write the eigenvectors as well as the phonon frequencies to file for the additional qpoints.  
Default Value: 
 
Example:  phonon_write_eigenvecs T  
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Syntax:  PLOT_NBO [Logical]  
Description:  Instructs ONETEP to read the relevant orbital transformation output from gennbo, determined by the flag NBO_PLOT_ORBTYPE and plots the orbitals specified in the NBO_LIST_PLOTNBO block. WRITE_NBO and PLOT_NBO are mutually exclusive. Scalar field plotting must be enabled (e.g. CUBE_FORMAT = T).  
Default Value: 
 
Example: 
plot_nbo T  
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Syntax:  POLARISATION_CALCULATE [Logical]
 
Description:  Activates the calculation of polarisation  
Default Value: 
 
Example: 
polarisation_calculate T  
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Syntax:  POLARISATION_SIMCELL_CALCULATE [Boolean]  
Description:  Turns on the calculation of polarisation in a properties calculation. Dipole moments and quadrupole moments are calculated for the entire system using the "simcell" approach (i.e. directly from integrals over real space). Both are calculated relative to a point defined by POLARISATION_SIMCELL_REFPT (default: 0.0 0.0 0.0).  
Default Value: 
 
Example: 
polarisation_simcell_calculate T  
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Syntax:  POPN_BOND_CUTOFF [Value] [Unit]
 
Description:  Specifies the bond length cutoff to use when performing Mulliken population analysis.  
Default Value: 
 
Example: 
popn_bond_cutoff 5.0 ang  
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Syntax:  POPN_CALCULATE [Logical]  
Description:  Perform Mulliken population analysis.
 
Default Value: 
 
Example: 
popn_calculate F  
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Syntax: 
 
Description:  Specifies the atomic positions as Cartesian coordinates). In the above syntax, Si denotes the species of atomi(max 4 characters) and Ri its position vector. Note that all atoms are currently required to be positioned within the simulation cell. By default, these will be interpreted as being in atomic units (a0), but they will be interpreted as being Angstroms if "ang" is on the first line of the block.  
Default Value:  
Example: 
 
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Syntax:  PPD_NPOINTS [Text]  
Description:  Specifies the size of the parallelepipeds (PPDs) used to group the simulation cell psinc grid points for efficiency. The size of the PPD is given by three integers corresponding to the number of grid points in the a1, a2 and a3 directions respectively. These integers must all be factors of the simulation cell psinc grid size in the relevant direction.
 
Default Value: 
 
Example: 
ppd_npoints 5 7 6  
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Syntax:  PRECOND_REAL [Logical]
 
Description:  Apply kinetic energy preconditioning by a convolution in realspace. See Mostofiet al.,J. Chem. Phys.119, 8842 (2003) for further details.  
Default Value: 
 
Example: 
precond_real T  
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Syntax:  PRECOND_RECIP [Logical]
 
Description:  Apply kinetic energy preconditioning by a multiplication in reciprocalspace. See Mostofiet al.,J. Chem. Phys.119, 8842 (2003) for further details.  
Default Value: 
 
Example: 
precond_recip F  
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Syntax:  PRECOND_SCHEME [Text]
 
Description:  Specifies the form of the kinetic energy preconditioner used, currently one of: BG  BowlerGillan scheme:Comput. Phys. Commun.112, 103 (1998) MAURI  Mauri scheme TETER  TeterPayneAllan scheme:Phys. Rev. B40, 12255 (1989) NONE  no kinetic energy preconditioning  
Default Value: 
 
Example: 
precond_scheme MAURI  
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Syntax:  PRINT_QC [Text]
 
Description:  Include a summary of the calculation in the output for the purposes of "quality control" on code modifications.  
Default Value: 
 
Example: 
print_qc T  
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Syntax:  PRODUCT_ENERGY [Physical]  
Description:  Both the reactant and product energies must be known at the start of a NEB calculation. The energy can be specified either as a raw total energy or as a rootname from which ONETEP can read the tightbox NGWF and density kernel (and, in EDFT, Hamiltonian) files from a previous calculation, or they can be calculated from scratch if neither is specified. The reactant and product energies needn’t be specified in the same way.
This keyword specifies the total energy of the product.  
Default Value: 
 
Example: 
product_energy 21102.843530 Ha  
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Syntax:  PRODUCT_ROOTNAME [Text]  
Description:  Both the reactant and product energies must be known at the start of a NEB calculation. The energy can be specified either as a raw total energy or as a rootname from which ONETEP can read the tightbox NGWF and density kernel (and, in EDFT, Hamiltonian) files from a previous calculation, or they can be calculated from scratch if neither is specified. The reactant and product energies needn’t be specified in the same way.
This keyword specifies the rootname of the .tightbox_ngwf, .dkn, and/or .ham files that ONETEP can read the product from.  
Default Value: 
 
Example: 
product_rootname my_prod_calculation  
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Syntax:  PROJECTORS_PRECALCULATE [Text]
 
Description:  Controls whether the projectors are all evaluated in FFTboxes simultaneously, whenever the projectorNGWF overlap or projector gradient is required. If true, all projectors are evaluated at once (requiring many FFTboxes and significant memory usage if many projectors are present). If false, only one projector is evaluated at a time (which is slower, as new projectors must be reevaluated many times over, but uses minimal memory).  
Default Value: 
 
Example: 
projectors_precalculate F  
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Syntax:  PSINC_SPACING [Text]
 
Description:  Specifies the spacing between psinc grid points in the simulation cell by three real values (in atomic units a0) in the a1,a2 and a3directions respectively. These spacings must all be factors of the simulation cell lengths in the relevant directions. By default, these will be interpreted as being in atomic units (a0), but any recognised unit symbol can be used after the third value to override to a specific choice of units.  
Default Value: 
 
Example: 
psinc_spacing 0.4 0.5 0.5 or
 
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Syntax:  REACTANT_ENERGY [Physical]  
Description:  Both the reactant and product energies must be known at the start of a NEB calculation. The energy can be specified either as a raw total energy or as a rootname from which ONETEP can read the tightbox NGWF and density kernel (and, in EDFT, Hamiltonian) files from a previous calculation, or they can be calculated from scratch if neither is specified. The reactant and product energies needn’t be specified in the same way.
This keyword specifies the total energy of the reactant.  
Default Value: 
 
Example: 
neb_reactant_energy 21102.843530 Ha  
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Syntax:  REACTANT_ROOTNAME [Text]  
Description:  Both the reactant and product energies must be known at the start of a NEB calculation. The energy can be specified either as a raw total energy or as a rootname from which ONETEP can read the tightbox NGWF and density kernel (and, in EDFT, Hamiltonian) files from a previous calculation, or they can be calculated from scratch if neither is specified. The reactant and product energies needn’t be specified in the same way.
This keyword specifies the rootname of the .tightbox_ngwf, .dkn, and/or .ham files that ONETEP can read the reactant from.  
Default Value: 
 
Example: 
reactant_rootname my_reac_calculation  
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Syntax:  READ_DENSKERN [Logical]
 
Description:  Read in the density kernel from disk. If the input filename is rootname.dat then the density kernel filename is rootname.denskern .  
Default Value: 
 
Example: 
read_denskern T  
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Syntax:  READ_HAMILTONIAN [Logical]  
Description:  Read the Hamiltonian matrix from a .ham file. Currently, only used for restarting EDFT calculations.
 
Default Value: 
 
Example: 
read_hamiltonian F  
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Syntax:  READ_MAX_L [Integer]
 
Description:  Specifies the maximum angular momentum of the spherical waves (l number) when reading from file.  
Default Value: 
 
Example: 
read_max_l 5  
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Syntax:  READ_SW_NGWFS [Logical]
 
Description:  Read in the NGWFs from disk in spherical waves format and generates a linear combination of SW to restart the NGWFs. If the input filename is rootname.dat then the NGWFs filename is rootname.sw_ngwfs .  
Default Value: 
 
Example: 
read_sw_ngwfs T  
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Syntax:  READ_TIGHTBOX_NGWFS [Logical]
 
Description:  Read in the NGWFs from disk. If the input filename is rootname.dat then the NGWFs filename is rootname.tightbox_ngwfs .  
Default Value: 
 
Example: 
read_tightbox_ngwfs T  
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Syntax:  RMS_KERNEL_MEASURE [Logical]  
Description:  Use a legacy measure of the commutator of the densitymatrix and Hamiltonian, given by the root mean squared value of the doublycovariant NGWF representation of their commutator.  
Default Value: 
 
Example: 
rms_kernel_measure T  
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Syntax:  RUN_TIME [Real]  
Description:  The maximum allocated run time for this job (in seconds). Certain iterative processes (NGWF CG, electronic transport etc) are timed on a periteration basis: if the timer detects that there is not enough time left before the total elapsed wall time reaches the value of run_time, then the iterative process will be halted to allow the code to exit gracefully.  
Default Value: 
 
Example: 
run_time 43000  
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Syntax:  R_PRECOND [Value] [Unit]  
Description:  Specifies the radius in atomic units (a0) of the realspace kinetic energy preconditioner (used to accelerate the convolution).
 
Default Value: 
 
Example: 
r_precond 1.5 bohr  
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Syntax:  SMOOTHING_FACTOR [Value]  
Description:  The electronic volume Ve used in the electronic enthalpy method is obtained by using a Heaviside step function smeared by a smoothing factor [ corresponding to alpha/sigma in Corsini et al, J. Chem. Phys. 2013, 139, 084117] for numerical reasons.  
Default Value: 
 
Example:  smoothing_factor 6.0  
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Syntax:  SMOOTH_PROJECTORS [Real]
 
Description:  Specifies the halfwidth in atomic units (a0) of a Gaussian filter used to smooth the nonlocal projectors. A negative value indicates that no smoothing should be applied.  
Default Value: 
 
Example: 
smooth_projectors 0.5  
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Syntax: 
 
Description:  Describes the kinds of Boltzmann ions in implicit solvent. Only relevant when solving the PoissonBoltzmann equation in implicit solvent. Each entry specifies a name (species), charge and concentration (in mol/L).  
Default Value: 
 
Example: 
 
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Syntax: 
 
Description:  Defines the atomic species. In the above syntax, Si denotes the species of atom i(max 4 characters), corresponding to the element with symbol Xi and atomic number ZN , and with which are associated ni NGWFs of radius RN . More than one atomic species may refer to the same element, e.g. so that different ionic constraints may be applied to them. By default, the radii will be interpreted as being in atomic units (a0), but they will be interpreted as being Angstroms if "ang" is on the first line of the block.  
Default Value:  
Example: 
 
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Syntax: 
 
Description:  Specifies the set of initial atomic or pseudoatomic orbitals which will be used to initialise the NGWFs. One can either specify "fireball" (truncated pseudoatomic orbital) files,or use AUTO to generate STO3G and 631G* basis functions, or one can use the builtin pseudoatomic solver, using "SOLVE". With "SOLVE", a configuration for the neutral pseudoatom is guessed on the basis of the ion charge and the atomic number, but this can be overridden. See the help file "pseudoatomic_solver.pdf" in the documentation folder (/doc in the distribution) for more information on how to use the pseudoatomic solver In the above syntax, Si denotes atomic species i(max 4 characters). automatically as required.  
Default Value: 
 
Example: 
 
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Syntax: 
 
Description:  Defines the atomic species used for conduction optimisation. The atomic species details must match those given in the SPECIES block, and the same guidelines apply. By default, the radii will be interpreted as being in atomic units (a0), but they will be interpreted as being Angstroms if "ang" is on the first line of the block.  
Default Value:  
Example: 
 
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Syntax: 
 
Description:  Defines the constraints for the atomic species for use during geometry optimization. In the above syntax, Si denotes atomic speciesi(max 4 characters). The constraint type is one of NONE (no constraint), FIXED (atom is constrained to remain fixed), LINE (atom is constrained to a line) or PLANE (atom is constrained to a plane). In the case of LINE and PLANE , three further real values are required, to specify the direction vector of the line or the normal vector to the plane (in Cartesian coordinates) respectively.  
Default Value:  
Example: 
 
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Syntax: 
 
Description:  Defines the groups of species identifiers for which the groups of an LDOS plot are defined. Each line defines a group with any number of entries allowed on the line. Species identifier labels must correspond to those defined in %block species .  
Default Value:  
Example: 
 
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Syntax: 
 
Description:  Defines the atomic species whose NGWFs are to be plotted during the calculation. In the above syntax, Si denotes atomic species i to plot.  
Default Value:  
Example: 
 
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Syntax: 
 
Description:  Specifies the pseudopotential files for the atomic species in a normconserving pseudopotential calculation, or the PAW potentials in a PAW Calculation. In the above syntax, Si denotes atomic species i (max 4 characters). Pseudopotential files can be in the CASTEP .recpot format or .usp format and must define normconserving pseudopotentials. PAW Potentials can be in the ABINIT .paw format.  
Default Value:  
Example: 
 
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Syntax:  SPIN [Integer]  
Description:  Specifies the total spin of the system in units of 1/2;h/(2pi). If the total spin is nonzero, a spinpolarized calculation will automatically be selected. Can be specified as a noninteger number in EDFT calculations.  
Default Value: 
 
Example: 
spin 1  
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Syntax:  SPIN_POLARIZED [Logical]  
Description:  Specifies that a spinpolarized calculation should be performed.
 
Default Value: 
 
Example: 
spin_polarized T  
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Syntax:  SPREAD_CALCULATE [Text]  
Description:  Activates the Calculation of NGWF spreads
 
Default Value: 
 
Example: 
spread_calculate T  
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Syntax: 
 
Description:  Within this block, the first line gives the shape of the supercell (2x2x2), and subsequent lines list the ions in the positions_abs_block that belong to the 'base' unit cell. When a supercell calculation is specified, only the ions within the unit cell are displaced, although the forces on all ions in the system are used to calculate the elements of the dynamical matrix. It is also possible to specify PHONON_VIB_FREE and PHONON_EXCEPTION_LIST in a supercell calculation, although only the ions listed in the supercell block can be included in the a href="#phonon_exception_list">PHONON_EXCEPTION_LIST block.  
Default Value: 
 
Example: 
In this example, we are defining a 2x2x2 supercell (for example for Si), with the ions of index 1 and 9 defining the "base" unit cell. Of course, a small supercell will not give sensible results for a phonon calculation. However, a good example would be a 1000atom cubic supercell of Si, which gives excellent results. %block supercell
 
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Syntax:  TASK [Text]
 
Description:  Specifies the task to be carried out, currently one of:SINGLEPOINT  single point energy calculationCOND  Conduction NGWF optimisation calculationPROPERTIES  properties using results from a previous calculation of the ground state. PROPERTIES_COND  properties using results from a previous calculation of the conduction NGWFs. GEOMETRYOPTIMIZATION  geometry optimization using Cartesian or delocalized internal coordinates. MOLECULARDYNAMICS  molecular dynamics simulation. TRANSITIONSTATESEARCH  transition state search PHONON  a phonon frequencies and thermodynamics calculation. HUBBARDSCF  a projectorselfconsistent DFT+U calculation.  
Default Value: 
 
Example: 
task GEOMETRYOPTIMIZATION  
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Syntax: 
 
Description:  Defines the molecular dynamics thermostat. For each thermostat, the first line should contain the following mandatory parameters,
Each thermostat may also be tuned using the options,
 
Default Value:  
Example: 
Let us set an NVT calculation at 300K with Langevin thermostat for the equilibration (3000 steps) and NoseHoover thermostat for the thermodynamical sampling (10000 steps). The input parameters could look like.
%block thermostat  
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Syntax:  THREADS_MAX [INTEGER]  
Description:  Number of OpenMP threads in outer loops.  
Default Value: 
 
Example: 
threads_max 4  
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Syntax:  THREADS_NUM_FFTBOXES [INTEGER]  
Description:  Number of threads to use in OpenMPparallel FFTs.  
Default Value: 
 
Example: 
threads_num_fftboxes 4  
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Syntax:  THREADS_NUM_MKL [INTEGER]  
Description:  The number of threads to use in MKL routines (matrixmatrix multiplications, inverses, diagonalisations etc.). ONETEP must be compiled against Intel's MKL library with the compile flag DMKLOMP. Currently only used in the calculation of electron transmission.  
Default Value: 
 
Example:  threads_num_mkl 2  
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Syntax:  THREADS_PER_CELLFFT [INTEGER]  
Description:  Number of threads to use in OpenMPparallel FFTs on simulation cell.  
Default Value: 
 
Example: 
threads_per_cellfft 4  
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Syntax:  THREADS_PER_FFTBOX [INTEGER]  
Description:  Number of nested threads used for FFT box operations.
This kind of threading requires an OpenMPenabled version of the FFTW library. Otherwise, this functionality should be disabled via the FFTW3_NO_OMP compilation flag.  
Default Value: 
 
Example: 
threads_per_fftbox 2  
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Syntax:  TIMINGS_LEVEL [Integer]
 
Description:  Specifies the amount of detail in the timing information collected:0  total time only reported1  timings for routines averaged across all processors2  timings for routines on all processors individually  
Default Value: 
 
Example: 
timings_level 0  
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Syntax:  TSSEARCH_CG_MAX_ITER [Integer]
 
Description:  Specifies the maximum number of conjugate gradients iterations for the transition state search.  
Default Value: 
 
Example: 
tssearch_cg_max_iter 30  
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Syntax:  TSSEARCH_DISP_TOL [Value] [Unit]  
Description:  Specifies atomic displacement tolerance used as one of the criteria for convergence of a transition state search. The positions of all atoms must change by less than this tolerance to satisfy this criterion.
 
Default Value: 
 
Example: 
tssearch_disp_tol 1.0e3 nm  
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Syntax:  TSSEARCH_ENERGY_TOL [Value] [Unit]  
Description:  Specifies the tolerance for enthalpy per atom over one NEB step for convergence.
 
Default Value: 
 
Example: 
tssearch_energy_tol 0.2 meV  
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Syntax:  TSSEARCH_FORCE_TOL [Value] [Unit]
 
Description:  Specifies the tolerance for maximum atomic force as a criterion for transition state search convergence. Note that units involving a forward slash (/) must be quoted as in the example below.  
Default Value: 
 
Example: 
tssearch_force_tol 0.05 'ev/ang'  
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Syntax:  TSSEARCH_LSTQST_PROTOCOL [Text]
 
Description:  Specifies the protocol for transition state search with the LSTQST method, currently one of LSTMAXIMUM , HALGRENLIPSCOMB , LST/OPTIMIZATION , COMPLETELSTQST or QST/OPTIMIZATION .  
Default Value: 
 
Example: 
tssearch_lstqst_protocol LST/OPTIMIZATION  
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Syntax:  TSSEARCH_METHOD [Text]  
Description:  Specifies the method for transition state search, LSTQST or NEB . If NEB is used, NUM_IMAGES should also be specified to set the number of NEB beads.  
Default Value: 
 
Example: 
tssearch_method NEB  
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Syntax:  TSSEARCH_QST_MAX_ITER [Integer]
 
Description:  Specifies the maximum number of QST iterations for the transition state search.  
Default Value: 
 
Example: 
tssearch_qst_max_iter 10  
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Syntax:  TURN_OFF_EWALD [Boolean]  
Description:  Elides the calculation of Ewald energy and force terms in the calculation. This is potentially useful in properties calculations, where the Ewald terms are known already from the singlepoint calculation and you don't want to spend time to recalculate them again.  
Default Value: 
 
Example: 
turn_off_ewald T  
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Syntax:  USE_SPACE_FILLING_CURVE [Logical]
 
Description:  Use a Hilbert spacefilling curve to distribute the atoms among processors in a parallel calculation.  
Default Value: 
 
Example: 
use_space_filling_curve F  
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Syntax:  USE_SPH_HARM_ROT [Boolean]  
Description:  When True, manually activate the sph_harm_rotation (spherical harmonic rotation) module (used to evaluate the metric matrix in the 2Dn1Da scheme for spherical wave metric matrix evaluation). In normal operation this is not necessary, since the module will be activated if it is detected that spherical harmonic rotation is required. Setting this to False has no effect, since the option will be overridden if ONETEP detects that the module is needed, anyway.  
Default Value: 
 
Example: 
use_sph_harm_rot T  
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Syntax:  VDW_DCOEFF [Real]  
Description:  Overrides the damping constant associated with a damping function.  
Default Value: 
 
Example: 
vdw_dcoeff 11  
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Syntax:  %block vdw_params nzatom_1 c6coeff_1 radzero_1 neff_1 nzatom_2 c6coeff_2 radzero_2 neff_2 ...... %endblock vdw_params  
Description:  This option allows the user to specify parameters for elements and functionals for which values are not given. The atomdependent variables C6_i (used to calculate C6_ij),R0_i (related to the atomic vdW radius of an atom i), and n_eff (used in the calculation of C6_ij for all damping functions excluding the D2 correction of Grimme) are modified using the VDW_PARAMS block. This override block applies the parameter changes to atoms by their atomic number (nzatom).  
Default Value:  
Example: 
For example, to override the disp ersion parameters asso ciated with nitrogen:
%block vdw_params  
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Syntax:  WRITE_CONVERGED_DKNGWFS [Logical]  
Description:  Specifies that the density kernel and NGWF output files should only be written at the end of a converged calculation, rather than after every iteration.
 
Default Value: 
 
Example: 
write_converged_dkngwfs T  
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Syntax:  WRITE_DENSITY_PLOT [Logical]
 
Description:  Specifies that the charge density, electrostatic potential and spin density (if appropriate) be written out for plottingif properties are requested.  
Default Value: 
 
Example: 
write_density_plot F  
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Syntax:  WRITE_DENSKERN [Logical]
 
Description:  Write the density kernel to disk. If the input filename is rootname.dat then the density kernel filename is rootname.denskern .  
Default Value: 
 
Example: 
write_denskern F  
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Syntax:  WRITE_FORCES [Logical]
 
Description:  Include the forces in the output of a single point energy calculation.  
Default Value: 
 
Example: 
write_forces T  
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Syntax:  WRITE_HAMILTONIAN [Logical]
 
Description:  Write the Hamiltonian matrix on a .ham file. Currently, only used in EDFT calculations. Set to true if a calculation is intended to be restarted at some point in the future.  
Default Value: 
 
Example: 
write_hamiltonian T  
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Syntax:  WRITE_MAX_L [Integer]
 
Description:  Specifies the maximum angular momentum of the spherical waves (l number) when writing to file.  
Default Value: 
 
Example: 
write_max_l 2  
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Syntax:  WRITE_NBO [Logical]  
Description:  Enables Natural Population Analysis (NPA) and writing of gennbo input file seedname_nao_nbo.47  
Default Value: 
 
Example: 
write_nbo T  
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Syntax:  WRITE_NGWF_PLOT [Logical]
 
Description:  Write out NGWFs for species listed in the SPECIES_NGWF_PLOT to disk for plotting during a single point energy calculation, in the cube and/or .grd formats as requested.  
Default Value: 
 
Example: 
write_ngwf_plot T  
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Syntax:  WRITE_SW_NGWFS [Logical]
 
Description:  Write the NGWFs to disk in spherical waves decomposition. If the input filename is rootname.dat then the NGWFs filename is rootname.sw_ngwfs .  
Default Value: 
 
Example: 
write_sw_ngwfs T  
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Syntax:  WRITE_TIGHTBOX_NGWFS [Logical]
 
Description:  Write the NGWFs to disk. If the input filename is rootname.dat then the NGWFs filename is rootname.tightbox_ngwfs .  
Default Value: 
 
Example: 
write_tightbox_ngwfs F  
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Syntax:  WRITE_XYZ [Logical]  
Description:  Write the atom coordinates to disk as an .xyz file
 
Default Value: 
 
Example: 
write_xyz T  
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Syntax:  XC_FUNCTIONAL [Text]  
Description:  Specifies the exchangecorrelation functional to use, currently one of:
 
Default Value: 
 
Example: 
xc_functional PBE  
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Syntax:  ZERO_TOTAL_FORCE [Logical]
 
Description:  Forces the total ionic force to be zero by subtracting the average ionic force from all ionic forces.  
Default Value: 
 
Example: 
zero_total_force F  
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