Documentation for specific functionality
At present we do not have a detailed full manual for the code. However, we do have documents explaining the use of certain elements of functionality.
Conduction NGWF Optimisation Δ
Pseudoatomic Solver Δ
Implicit Solvation Δ
Realspace Local Pseudopotentials Δ
DFT+U Calculations (also called LDA+U) Δ
Phonon Calculations Δ
Local Density of States Calculations Δ
Natural Bond Orbital Calculations Δ
Van der Waals Density Functional Calculations Δ
BornOppenheimer Molecular Dynamics Δ
Finitetemperature EnsembleDFT calculations Δ
Density kernel and Hamiltonian mixing (kernel_diis) Δ
LinearResponse TimeDependent DFT calculations (lr_tddft) Δ
Empirical dispersion corrections (dispersion) Δ
Constrained DFT keyword list Δ (work in progress)
Constrained DFT input file checklist Δ (work in progress)
For general help on standard total energy and force calculations, see the tutorials and the input file documentation below.
Documentation for input files
ONETEP calculations are defined by a single freeformat input file with a .dat extension. Comments are introduced by the characters #, ; or !. The keywords are divided into three levels: basic, intermediate and expert, and may be of several types.
Go to: Basic  Intermediate  Expert  Top
Basic keywords
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_PLOT_JOINT_ORBITALS
 Logical  Plot orbitals in joint valcond 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_KERNEL_CUTOFF
 Real  Conduction state density kernel cutoff radius in bohr. 
COND_NUM_STATES
 Logical  The number of conduction states to be optimised. 
COND_INIT_SHIFT
 Real  Initial shifting factor for projected cond Hamiltonian. 
COND_SHIFT_BUFFER
 Real  Buffer added to highest calculated eigenvalue when updating cond shift 
COND_FIXED_SHIFT
 Logical  Keep shift for projected conduction Hamiltonian constant in COND task 
COND_CALC_MAX_EIGEN
 Logical  Calc maximum cond Hamiltonian eigenvalue at each NGWF CG opt step 
COND_CALC_OPTICAL_SPECTRA
 Logical  Calculate matrix elements for use in optical absorption spectra 
COND_SPEC_CALC_MOM_MAT_ELS
 Logical  Calculate optical matrix elements in momentum representation 
COND_SPEC_CALC_NONLOC_COMM
 Logical  Calculate commutator between nonloc pot and position operator 
COND_SPEC_CONT_DERIV
 Logical  Calculate commutator between the nonloc pot and pos operator using continuous derivative in kspace 
COND_SPEC_NONLOC_COMM_SHIFT
 Real  Finite difference shift for calculating commutator between nonloc pot and the pos operator 
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 
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_MAXIT
 Integer  Maximum number of inner loop iterations with the EDFT method. 
EDFT_SMEARING_WIDTH
 Physical  Occupation smearing width for EDFT calculations. 
FINE_GRID_SCALE
 Real  Spacing of fine grid as multiple of standard grid 
GEOM_MAX_ITER
 Integer  Maximum number of geometry optimisation iterations 
GEOM_METHOD
 Text  Geometry optimisation method 
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 
IS_BULK_PERMITTIVITY
 Real  Defines the relative dielectric permittivity of the solvent 
IS_IMPLICIT_SOLVENT
 Logical  Makes the calculation use implicit solvent 
IS_INCLUDE_CAVITATION
 Logical  Turns on the cavitation term in an implicit solvent calculation 
IS_SOLVENT_SURFACE_TENSION
 Physical  Defines the surface tension of the solvent 
KERNEL_CUTOFF
 Real  Density kernel cutoff radius in bohr 
LATTICE_CART
 Block  Simulation cell lattice vectors in Cartesian coordinates 
LUMO_PLOT
 Integer  Number of canonical orbitals to plot above LUMO 
LUMO_DENS_PLOT
 Integer  Number of canonical orbital densities to plot above LUMO 
MD_DELTA_T
 Physical  Molecular dynamics time step 
MD_NUM_ITER
 Integer  Number of molecular dynamics iterations 
MD_RESET_DKN_NGWFS
 Integer  Full reset of the NGWFs and density kernel SCF cycle every Nth time steps 
MD_RESTART
 Logical  Restart MD from previous backup files 
NNHO
 Logical  Convert NGWFs into nonorthogonal natural hybrid orbitals 
OUTPUT_DETAIL
 Text  Specify level of output detail 
PAW
 Logical  Activate PAW calculation. 
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 
SPECIES
 Block  Atomic species information 
SPECIES_COND
 Block  Atomic species information for conduction NGWFs 
SPECIES_LDOS_GROUPS
 Block  Local Density of States species group definitions 
SPECIES_CONSTRAINTS
 Block  Atomic species geometry optimisation constraints 
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 
TASK
 Text  Specify task 
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_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 
Go to: Basic  Intermediate  Expert  Top
Intermediate keywords
Keyword  Type  Description 
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 
COND_NUM_EXTRA_STATES
 Integer  Num additional conduction states optimised during preoptimisation stage 
COND_NUM_EXTRA_ITS
 Integer  Number of iterations of preoptimisation stage during COND task 
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 
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
 Logical  Compute electronic transmission coefficients as a function of energy 
ETRANS_ECMPLX
 Physical  Imaginary energy accounting for the boundary conditions of the retarded Green's function 
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_SAME_LEADS
 Logical  Use the same selfenergy for all the leads 
ETRANS_SETUP
 Block  Transport setup description 
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_PREF
 Text  Preferred FFT box size 
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_MODULUS_EST
 Physical  Estimated bulk modulus for geometry optimisation 
HUBBARD
 Block  Activate DFT+U, or LDA+U, functionality 
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_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_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
 Real  Characteristic width for the Gaussian smearing of ions (atomic units) 
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_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 
KERNEL_DIIS_MAXIT
 Integer  Maximum number of inner loop DIIS iterations 
LDOS_SMEAR
 Physical  Halfwidth for Gaussian smearing of local density of states 
LIBXC_X_FUNC_ID
 Integer  Functional ID for exchange functional in a LIBXC calculation. 
LIBXC_C_FUNC_ID
 Integer  Functional ID for correlation functional in a LIBXC calculation. 
LNV_THRESHOLD_ORIG
 Real  Convergence threshold for density kernel RMS gradient 
LNV_CHECK_TRIAL_STEPS
 Logical  Check stability of kernel at each trial step during LNV 
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 
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 
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 
POSITIONS_ABS_INTERMEDIATE
 Block  Intermediate atomic positions in Cartesian coordinates for transition state search 
POSITIONS_ABS_PRODUCT
 Block  Product atomic positions in Cartesian coordinates for transition state search 
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 
SPECIES_ATOMIC_SET
 Block  Atomic species initial NGWFs 
THERMOSTAT
 Block  Molecular dynamics thermostat 
TIMINGS_LEVEL
 Integer  Set level of detail in timings 
TSSEARCH_DISP_TOL
 Physical  Transition state search displacement tolerance 
TSSEARCH_FORCE_TOL
 Physical  Transition state search force tolerance 
TSSEARCH_METHOD
 Text  Transition state search method 
TSSEARCH_LSTQST_PROTOCOL
 Text  Transition state search LSTQST protocol 
WRITE_CONVERGED_DKNGWFS
 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 
Go to: Basic  Intermediate  Expert  Top
Expert keywords
Keyword  Type  Description 
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 
DELTA_E_CONV
 Logical  Use consecutive energy gains as NGWF convergence criterion 
DENSITY_BATCH_SIZE
 Integer  Batch size for NGWF communications during density evaluation 
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 
GEOM_PRINT_INV_HESSIAN
 Logical  Print inverse Hessian 
GEOM_REUSE_DK_NGWFS
 Logical  Reuse density kernel and NGWFs during geometry optimisation steps 
GEOM_RESET_DK_NGWFS_ITER
 Logical  Number of geom iterations between resets of kernel and NGWFs 
IS_BC_THRESHOLD
 Real  Charge density threshold for bulk charge coarsegraining in open boundary conditions 
INITIAL_DENS_REALSPACE
 Real  Construct initial density in real space from atomsolver density 
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_SURFACE_THICKNESS
 Real  Surface film thickness (in atomic units of charge density) used for the determination of cavity surface area 
K_ZERO
 Real  Parameter for kinetic energy preconditioning in inverse bohr 
KERNEL_DIIS_THRESHOLD
 Real  Convergence threshold 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_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_LSHIFT
 Physical  Levelshifting energy during inner loop DIIS. 
KERNEL_DIIS_LS_ITER
 Integer  Number of inner loop DIIS iterations with levelshifting enabled. 
KERNEL_UPDATE
 Logical  Update density kernel during NGWF line search 
KINETIC_INT_BATCH_SIZE
 Integer  Batch size for NGWF communications during kinetic energy integrals 
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_INT_BATCH_SIZE
 Integer  Batch size for NGWF communications during local potential integrals 
LOCPOT_SCHEME
 Text  Scheme for symmetrising local potential matrix 
MAX_RESID_HOTELLING
 Real  Maximum residual value allowed when inverting overlap matrix 
MIX_DENSKERN_NUM
 Integer  Number of independent coefficients used to build new guesses for the density kernel 
MIX_DENSKERN_TYPE
 Integer  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_NUM
 Integer  Number of independent coefficients used to build new guesses for the NGWFs 
MIX_NGWFS_TYPE
 Integer  Type of mixing used to build new guesses for the NGWFs 
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_GRAD_BATCH_SIZE
 Integer  Batch size for NGWF communications during NGWF gradient evaluation 
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
 Real  Turn on MartynaTuckerman correction to the effects of periodic boundary conditions, with a specified dimensionless cutoff. 
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 
R_PRECOND
 Real  Radial cutoff for realspace preconditioning in bohr 
PSINC_SPACING
 Text  Psinc grid spacing in bohr 
R_PRECOND
 Real  Radial cutoff for realspace preconditioning in bohr 
SMOOTH_PROJECTORS
 Real  Halfwidth of Gaussian filter for smoothing nonlocal projectors in bohr 
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 
USE_SPACE_FILLING_CURVE
 Logical  Distribute atoms according to a spacefilling curve 
VERBOSE_EWALD_FORCES
 Logical  Print full details of Ewald forces 
ZERO_TOTAL_FORCE
 Logical  Subtract average ionic force from all forces to make the total ionic force zero 
BS_KPOINT_PATH
Syntax:  BS_KPOINT_PATH [Block]

Syntax: 

Description:  Kpoint path for bandstructure calculation. 
Example: 

Go to: Basic  Intermediate  Expert  Top
BS_KPOINT_PATH_SPACING
Syntax:  BS_KPOINT_PATH_SPACING [Physical]

Description:  Kpoint spacing along the bandstructure path. 
Default:  0.1889727 "1/bohr" 
Example:  bs_kpoint_path_spacing 0.004 "1/bohr"

Go to: Basic  Intermediate  Expert  Top
BS_METHOD
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:  TB 
Example:  bs_method kp

Go to: Basic  Intermediate  Expert  Top
BS_NUM_EIGENVALUES
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:  all eigenvalues 
Example:  bs_num_eigenvalues 10

Go to: Basic  Intermediate  Expert  Top
CHARGE
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:  0 ; charge neutral 
Example:  charge +1

Go to: Basic  Intermediate  Expert  Top
CHECK_ATOMS
Syntax:  CHECK_ATOMS [Logical]

Description:  Perform a check on the atomic positions to ensure that no two atoms are unphysically close. 
Default:  True 
Example:  check_atoms F

Go to: Basic  Intermediate  Expert  Top
CLASSICAL_INFO
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.

Example: 

Go to: Basic  Intermediate  Expert  Top
COMMS_GROUP_SIZE
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:  4 
Example:  comms_group_size 16

Go to: Basic  Intermediate  Expert  Top
COND_PLOT_JOINT_ORBITALS
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:  True 
Example:  cond_plot_joint_orbitals F

Go to: Basic  Intermediate  Expert  Top
COND_PLOT_VC_ORBITALS
Syntax:  COND_PLOT_VC_ORBITALS [Logical]

Description:  Plot orbitals in the separate valence and conduction NGWF basis sets following a conduction calculation. Applies to HOMO_PLOT and LUMO_PLOT . See also COND_PLOT_VC_ORBITALS .

Default:  True 
Example:  cond_plot_vc_orbitals F

Go to: Basic  Intermediate  Expert  Top
COND_READ_DENSKERN
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:  False 
Example:  cond_read_denskern T

Go to: Basic  Intermediate  Expert  Top
COND_READ_TIGHTBOX_NGWFS
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:  False 
Example:  cond_read_tightbox_ngwfs T

Go to: Basic  Intermediate  Expert  Top
COND_KERNEL_CUTOFF
Syntax:  COND_KERNEL_CUTOFF [Real]

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:  1000.0 ; i.e. effectively infinite 
Example:  cond_kernel_cutoff 25.0

Go to: Basic  Intermediate  Expert  Top
COND_NUM_STATES
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:  Equal to the number of valence electrons 
Example:  cond_num_states 20

Go to: Basic  Intermediate  Expert  Top
COND_INIT_SHIFT
Syntax:  COND_INIT_SHIFT [Real]

Description:  Initial shifting factor for projected conduction Hamiltonian, added to each eigenvalue. 
Default:  0.0 
Example:  cond_init_shift 1.0

Go to: Basic  Intermediate  Expert  Top
COND_SHIFT_BUFFER
Syntax:  COND_SHIFT_BUFFER [Real]

Description:  Additional buffer to add to the highest calculated eigenvalue when updating the shift for the projected conduction Hamiltonian. 
Default:  0.1 
Example:  cond_shift_buffer 0.5

Go to: Basic  Intermediate  Expert  Top
COND_FIXED_SHIFT
Syntax:  COND_FIXED_SHIFT [Logical]

Description:  Keep the shift for the projected conduction Hamiltonian constant throughout the calculation. 
Default:  False 
Example:  cond_fixed_shift T

Go to: Basic  Intermediate  Expert  Top
COND_CALC_MAX_EIGEN
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:  True 
Example:  cond_calc_max_eigen

Go to: Basic  Intermediate  Expert  Top
COND_CALC_OPTICAL_SPECTRA
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:  False 
Example:  cond_calc_optical_spectra T

Go to: Basic  Intermediate  Expert  Top
COND_SPEC_CALC_MOM_MAT_ELS
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:  True 
Example:  cond_spec_calc_mom_mat_els F

Go to: Basic  Intermediate  Expert  Top
COND_SPEC_CALC_NONLOC_COMM
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:  True 
Example:  cond_spec_calc_nonloc_comm F

Go to: Basic  Intermediate  Expert  Top
COND_SPEC_CONT_DERIV
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:  True 
Example:  cond_spec_cont_deriv F

Go to: Basic  Intermediate  Expert  Top
COND_SPEC_NONLOC_COMM_SHIFT
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:  0.0001 
Example:  cond_spec_nonloc_comm_shift 0.00001

Go to: Basic  Intermediate  Expert  Top
COND_NUM_EXTRA_STATES
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:  0 
Example:  cond_num_extra_states 10

Go to: Basic  Intermediate  Expert  Top
COND_NUM_EXTRA_ITS
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:  0 
Example:  cond_num_extra_its 5

Go to: Basic  Intermediate  Expert  Top
CONSTANT_EFIELD
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:  0.0 0.0 0.0 ; zero field 
Example:  constant_efield 1.0e3 0.0 0.0

Go to: Basic  Intermediate  Expert  Top
COREHAM_DENSKERN_GUESS
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:  True 
Example:  coreham_denskern_guess F

Go to: Basic  Intermediate  Expert  Top
CUBE_FORMAT
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:  False 
Example:  cube_format T

Go to: Basic  Intermediate  Expert  Top
COULOMB_CUTOFF_LENGTH
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:  0 
Example:  coulomb_cutoff_length 100 bohr

Go to: Basic  Intermediate  Expert  Top
COULOMB_CUTOFF_RADIUS
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:  0 
Example:  coulomb_cutoff_radius 100 bohr

Go to: Basic  Intermediate  Expert  Top
COULOMB_CUTOFF_TYPE
Syntax:  COULOMB_CUTOFF_RADIUS [Value]

Description:  Activates Cutoff Coulomb interactions, and chooses which type of cutoff to apply. Allowed values are: NONE, SPHERE, CYLINDER, SLAB, WIRE. 
Default:  NONE 
Example:  coulomb_cutoff_type SPHERE

COULOMB_CUTOFF_WRITE_INT
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:  F 
Example:  coulomb_cutoff_write_int T

Go to: Basic  Intermediate  Expert  Top
CUTOFF_ENERGY
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:  20 Ha 
Example:  cutoff_energy 500 eV

Go to: Basic  Intermediate  Expert  Top
DELTA_E_CONV
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:  True 
Example:  delta_e_conv F

Go to: Basic  Intermediate  Expert  Top
DENSITY_BATCH_SIZE
Syntax:  DENSITY_BATCH_SIZE [Integer]

Description:  Specifies the number of NGWFs to communicate in a single batch during the evaluation of the electronic density. May be used for tuning parallel performance, especially if "stack full" warnings are reported. 
Default:  10 
Example:  density_batch_size 5

Go to: Basic  Intermediate  Expert  Top
DENSE_THRESHOLD
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:  0.35 
Example:  dense_threshold 0.80

Go to: Basic  Intermediate  Expert  Top
DISPERSION
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), 669\u2013683 for more details. 
Default:  0 
Example:  dispersion 1

Go to: Basic  Intermediate  Expert  Top
DO_PROPERTIES
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:  False 
Example:  do_properties T

Go to: Basic  Intermediate  Expert  Top
DOS_SMEAR
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:  0.1 eV 
Example:  dos_smear 7 mRy

Go to: Basic  Intermediate  Expert  Top
DX_FORMAT
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:  False 
Example:  dx_format T

New in:  2.4.12 
Go to: Basic  Intermediate  Expert  Top
DX_FORMAT_COARSE
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:  False 
Example:  dx_format_coarse T

New in:  2.4.12 
Go to: Basic  Intermediate  Expert  Top
DX_FORMAT_DIGITS
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:  7 (that is, 1 before and 6 after the decimal point) 
Example:  dx_format_digits 12

New in:  2.4.12 
Go to: Basic  Intermediate  Expert  Top
EDFT
Syntax:  EDFT [Logical]

Description:  Enable finitetemperature DFT calculations with the EnsembleDFT method. Recommended for calculations on metallic systems. 
Default:  F 
Example:  edft T

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_MAXIT
Syntax:  EDFT_MAXIT [Integer]

Description:  Maximum number of inner loop iterations in calculations with the EDFT method. 
Default:  10 
Example:  edft_maxit 5

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_SMEARING_WIDTH
Syntax:  EDFT_SMEARING_WIDTH [Value] [Unit]

Description:  Occupation smearing width in EDFT calculations, based on the FermiDirac distribution. 
Default:  0.1 eV 
Example:  edft_smearing_width 0.2 eV

Example:  edft_smearing_width 800 K (sets the electronic temperature to 800 degree Kelvin)

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_COMMUTATOR_THRES
Syntax:  EDFT_COMMUTATOR_THRES [Value] [Unit]

Description:  Tolerance threshold for the Hamiltoniandensity matrix commutator during the EDFT inner loop. 
Default:  1.0e5 Hartree 
Example:  edft_commutator_thres 1.0e6

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_ENERGY_THRES
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:  1.0e6 Hartree 
Example:  edft_energy_thres 1.0e4 eV

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_ENTROPY_THRES
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:  1.0e6 Hartree 
Example:  edft_entropy_thres 1.0e5 eV

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_FERMI_THRES
Syntax:  EDFT_FERMI_THRES [Value] [Unit]

Description:  Tolerance threshold for the maximum change of the Fermi energy during two consecutive EDFT inner loop 
Default:  1.0e3 Hartree 
Example:  edft_fermi_thres 1.0e4 eV

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_FREE_ENERGY_THRES
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:  1.0e6 Hartree 
Example:  edft_free_energy_thres 1.0e4 eV

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_RMS_GRADIENT_THRES
Syntax:  EDFT_RMS_GRADIENT_THRES [Value]

Description:  Tolerance threshold for the maximum occupancies RMS gradient during the EDFT inner loop. 
Default:  1.0e4 
Example:  edft_rms_gradient_thres 1.0e5

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_EXTRA_BANDS
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:  1 
Example:  edft_extra_bands 16

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_MAX_STEP
Syntax:  EDFT_MAX_STEP [Value]

Description:  Maximum step during the EDFT inner loop line search. 
Default:  1.0 
Example:  edft_max_step 0.8

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_ROUND_EVALS
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:  1 
Example:  edft_round_evals 5

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EDFT_WRITE_OCC
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:  False 
Example:  edft_write_occ T

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EIGENSOLVER_ABSTOL
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:  1.0e9 
Example:  eigensolver_abstol 1.0e5

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
EIGENSOLVER_ORFAC
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:  1.0e4 
Example:  eigensolver_abstol 1.0e3

New in:  3.4 
Go to: Basic  Intermediate  Expert  Top
ELEC_CG_MAX
Syntax:  ELEC_CG_MAX [Integer]

Description:  Specifies the maximum number of NGWF conjugate gradients iterations between resets. 
Default:  5 
Example:  elec_cg_max 1 ; steepest descents

Go to: Basic  Intermediate  Expert  Top
ELEC_ENERGY_TOL
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:  0.001 eV 
Example:  elec_energy_tol 0.00001 eV

Go to: Basic  Intermediate  Expert  Top
ELEC_FORCE_TOL
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:  0.001 "ha/bohr" 
Example:  elec_force_tol 0.01 "eV/ang"

Go to: Basic  Intermediate  Expert  Top
ETRANS_CALCULATE
Syntax:  ETRANS_CALCULATE [Logical]

Description:  Computes the electronic transmission coefficients as a function of the energy. See ETRANS_SETUP for the description of the transport setup.

Default:  False 
Example:  etrans_calculate T

Go to: Basic  Intermediate  Expert  Top
ETRANS_ECMPLX
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. However, too small values of etrans_cmplx could lead to instabilities in the calculation of the leads selfenergies. 
Default:  0.001 "hartree" 
Example:  etrans_ecmplx 0.00001 "hartree"

Go to: Basic  Intermediate  Expert  Top
ETRANS_EMAX
Syntax:  ETRANS_EMAX [Value] [Unit]

Description:  Highest energy for the calculation of the transmission coefficients (defined with respect to the computed Fermi level). 
Default:  0.2 "hartree" 
Example:  etrans_emax 0.2 "hartree"

Go to: Basic  Intermediate  Expert  Top
ETRANS_EMIN
Syntax:  ETRANS_EMIN [Value] [Unit]

Description:  Lowest energy for the calculation of the transmission coefficients (defined with respect to the computed Fermi level). 
Default:  0.2 "hartree" 
Example:  etrans_emin 0.2 "hartree"

Go to: Basic  Intermediate  Expert  Top
ETRANS_ENUM
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:  50 
Example:  etrans_enum 100

Go to: Basic  Intermediate  Expert  Top
ETRANS_SAME_LEADS
Syntax:  ETRANS_SAME_LEADS [Logical]

Description:  Defines whether the source and drain leads are equivalent (i.e. identical sets of ordered atoms directly related by means of a rigid body translation) or not. When this flag is set to true, the code only computes the selfenergy associated with the source lead, saving some computational time. 
Default:  False 
Example:  etrans_same_leads T

Go to: Basic  Intermediate  Expert  Top
ETRANS_SETUP
Syntax: 

Description:  Defines the transport setup used for the calculation of the transport coefficients. The block should contain two lines referring respectively to the "source" and "drain" leads. Each line should contain two entries corresponding respectively to the first and last atoms to be included in the lead. This block is mandatory when ETRANS_CALCULATE is set to true.

Example: 
In this example, the leads are made up from the atoms [61,120] and [361,420]. Note that the code assumes that those leads respectively couple with the central region via the atoms [121,180] and [301,360]. Eventually, the retarded Green's function associated will be computed for the atoms [61,420] (i.e. all other atoms are considered as "buffer atoms").

Go to: Basic  Intermediate  Expert  Top
EXACT_LNV
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:  True 
Example:  exact_lnv F

Go to: Basic  Intermediate  Expert  Top
EXTRA_N_SW
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:  0 
Example:  extra_n_sw 10

Example:  extra_n_sw 5

Go to: Basic  Intermediate  Expert  Top
FINE_GRID_SCALE
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:  2.0 ; 
Example:  fine_grid_scale 4.0

Go to: Basic  Intermediate  Expert  Top
FFTBOX_PREF
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:  0 0 0 ; use smallest possible 
Example:  fftbox_pref 65 65 65

Go to: Basic  Intermediate  Expert  Top
GEOM_BACKUP_ITER
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:  1 ; every iteration 
Example:  geom_backup_iter 5

Go to: Basic  Intermediate  Expert  Top
GEOM_CONTINUATION
Syntax:  GEOM_CONTINUATION [Logical]

Description:  Continue a geometry optimization from a previous run using the .continuation backup file.

Default:  False 
Example:  geom_continuation T

Go to: Basic  Intermediate  Expert  Top
GEOM_CONVERGENCE_WIN
Syntax:  GEOM_CONVERGENCE_WIN [Integer]

Description:  Specifies the number of consecutive iterations during which the convergence criteria must be met. 
Default:  2 
Example:  geom_convergence_win 3

Go to: Basic  Intermediate  Expert  Top
GEOM_DISP_TOL
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:  103a0 
Example:  geom_disp_tol 1.0e4 nm

Go to: Basic  Intermediate  Expert  Top
GEOM_ENERGY_TOL
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:  106Ha per atom 
Example:  geom_energy_tol 0.2 meV

Go to: Basic  Intermediate  Expert  Top
GEOM_FORCE_TOL
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:  0.002 Ha/Bohr 
Example:  geom_force_tol 0.1 "ev/ang"

Go to: Basic  Intermediate  Expert  Top
GEOM_FREQUENCY_EST
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:  0.0073 Ha 
Example:  geom_frequency_est 0.2 eV

Go to: Basic  Intermediate  Expert  Top
GEOM_MAX_ITER
Syntax:  GEOM_MAX_ITER [Integer]

Description:  Specifies the maximum number of iterations for geometry optimisation. 
Default:  10 
Example:  geom_max_iter 30

Go to: Basic  Intermediate  Expert  Top
GEOM_METHOD
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:  CARTESIAN 
Example:  geom_method DELOCALIZED

Go to: Basic  Intermediate  Expert  Top
GEOM_MODULUS_EST
Syntax:  GEOM_MODULUS_EST [Value] [Unit]

Description:  Specifies the estimated bulk modulus used to initialize the inverse Hessian matrix for geometry optimization. 
Default:  500 Ha/a03 
Example:  geom_modulus_est 100 GPa

Go to: Basic  Intermediate  Expert  Top
GEOM_PRINT_INV_HESSIAN
Syntax:  GEOM_PRINT_INV_HESSIAN [Logical]

Description:  Include information about the inverse Hessian matrix in the ouput of a geometry optimization. 
Default:  False 
Example:  geom_print_inv_hessian T

Go to: Basic  Intermediate  Expert  Top
GEOM_REUSE_DK_NGWFS
Syntax:  GEOM_REUSE_DK_NGWFS [Logical]

Description:  Reuse density kernel and NGWFs during geometry optimisation steps 
Default:  T 
Example:  geom_reuse_dk_ngwfs F

Go to: Basic  Intermediate  Expert  Top
GEOM_RESET_DK_NGWFS_ITER
Syntax:  GEOM_RESET_DK_NGWFS_ITER [Integer]

Description:  Number of geom iterations between resets of kernel and NGWFs 
Default:  6 
Example:  geom_reset_dk_ngwfs_iter 20

Go to: Basic  Intermediate  Expert  Top
GRD_FORMAT
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:  True 
Example:  grd_format F

Go to: Basic  Intermediate  Expert  Top
HOMO_DENS_PLOT
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:  5 ; plot the HOMO and the five canonical orbitals below 
Example:  homo_dens_plot 0

Go to: Basic  Intermediate  Expert  Top
HOMO_PLOT
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:  5 ; plot the HOMO and the five canonical orbitals below 
Example:  homo_plot 0

Go to: Basic  Intermediate  Expert  Top
HUBBARD
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). An effective nuclear charge Z defines the hydrogenic orbitals spanning this subspace unless a negative value is given, e.g., Z=10 , in which case the NGWF initial guess orbitals (numerical atomic orbitals) are used. The a and s parameters (eV) are a rigid potential shift and a spinsplitting, respectively, applied to the subspaces.

Example: 

Go to: Basic  Intermediate  Expert  Top
INITIAL_DENS_REALSPACE
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:  F 
Example:  initial_dens_realspace T

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_AUTO_SOLVATION
Syntax:  IS_AUTO_SOLVATION [Logical]

Description:  Specifies that a calculation in vacuum should be automatically performed before any calculation that employs implicit solvent. 
Default:  F 
Example:  is_auto_solvation T

New in:  3.5.7.3 
Go to: Basic  Intermediate  Expert  Top
IS_BC_COARSENESS
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:  5 
Example:  is_bc_coarseness 7 ; Use blocks 7x7x7

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_BC_SURFACE_COARSENESS
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:  1 
Example:  is_bc_surface_coarseness 3 ; Use surface blocks of 3x3

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_BC_THRESHOLD
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:  1E9 
Example:  is_bc_threshold 1E10 ; Be extra accurate

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_BULK_PERMITTIVITY
Syntax:  IS_BULK_PERMITTIVITY [Value]

Description:  Sets the relative dielectric permittivity of the solvent. 
Default:  80.0 if IS_IMPLICIT_SOLVENT T , 1.0 if IS_IMPLICIT_SOLVENT F

Example:  IS_BULK_PERMITTIVITY 14.2 ; ethanediamine as solvent

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_CHECK_SOLV_ENERGY_GRAD
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:  F 
Example:  IS_CHECK_SOLV_ENERGY_GRAD T

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_DENSITY_THRESHOLD
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:  0.00078 
Example:  IS_DENSITY_THRESHOLD 0.00035

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_DIELECTRIC_FUNCTION
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:  FGF 
Example:  IS_DIELECTRIC_FUNCTION FGF

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_DIELECTRIC_MODEL
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:  FIX_INITIAL 
Example:  IS_DIELECTRIC_MODEL SELF_CONSISTENT

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_DISCRETIZATION_ORDER
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:  8 
Example:  IS_DISCRETIZATION_ORDER 10

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_IMPLICIT_SOLVENT
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:  F 
Example:  IS_IMPLICIT_SOLVENT T

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_INCLUDE_CAVITATION
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:  F 
Example:  IS_INCLUDE_CAVITATION T

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_MULTIGRID_DEFECT_ERROR_TOL
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:  0.01 
Example:  IS_MULTIGRID_DEFECT_ERROR_TOL 1E4 ; Try a stricter tolerance in case defectcorrection diverges

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_MULTIGRID_ERROR_TOL
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:  1E5 
Example:  IS_MULTIGRID_ERROR_TOL 1E4 ; Try a relaxed tolerance to speed calculation up

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_MULTIGRID_MAX_ITERS
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:  100 
Example:  IS_MULTIGRID_MAX_ITERS 200 ; purposefully waste time

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_MULTIGRID_NLEVELS
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:  4 
Example:  IS_MULTIGRID_NLEVELS 3

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_SEPARATE_RESTART_FILES
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:  F 
Example:  IS_SEPARATE_RESTART FILES T

New in:  3.5.3.2 
Go to: Basic  Intermediate  Expert  Top
IS_SMEARED_ION_REP
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:  F 
Example:  IS_SMEARED_ION_REP T

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_SMEARED_ION_WIDTH
Syntax:  IS_SMEARED_ION_WIDTH [Value]

Description:  Sets the smearing width for smeared ions (in atomic units). This is only relevant when IS_SMEARED_ION_REP is @T@. Values larger than default, especially larger than 1.0, are likely to lead to nonphysical results in implicit solvent calculations. Values smaller than default, especially smaller than 0.6 will negatively impact the convergence of the multigrid.

Default:  0.8 
Example:  IS_SMEARED_ION_WIDTH 0.6

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_SOLVATION_BETA
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:  1.3 
Example:  IS_SOLVATION_BETA 1.6

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_SOLVATION_METHOD
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:  DIRECT 
Example:  IS_SOLVATION_METHOD DIRECT

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_SOLVATION_OUTPUT_DETAIL
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:  NONE 
Example:  IS_SOLVATION_OUTPUT_DETAIL SOME

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_SOLVENT_SURFACE_TENSION
Syntax:  IS_SOLVENT_SURFACE_TENSION [Value] [Unit]

Description:  Sets the surface tension of the solvent. This is only relevant in implicit solvent calculations. 
Default:  4.7624E5 Ha/bohr**2 (corresponding to H2O) 
Example:  IS_SOLVENT_SURFACE_TENSION 1.33859E5 ha/bohr**2 ; corresponds to H2O with approximate inclusion of dispersionrepulsion

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
IS_SURFACE_THICKNESS
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:  0.0002 
Example:  IS_SURFACE_THICKNESS 0.0003

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
KERNEL_CUTOFF
Syntax:  KERNEL_CUTOFF [Real]

Description:  Specifies the density kernel spatial cutoff in atomic units (a0). Matrix elements are only included if the corresponding NGWF centres are closer than this distance. 
Default:  1000.0 ; i.e. effectively infinite 
Example:  kernel_cutoff 25.0

Go to: Basic  Intermediate  Expert  Top
KERNEL_DIIS_SCHEME
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:  NONE 
Example:  kernel_diis_scheme DKN_PULAY

New in:  3.5.2.9 
Go to: Basic  Intermediate  Expert  Top
KERNEL_DIIS_COEFF
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. CancÃ¨s, and C. Le Bris, Int. J. Quantum Chem. 79(2):82, 2000. E. CancÃ¨s, J. Chem. Phys. 114(24):10616, 2001. 
Default:  0.1000 
Example:  kernel_diis_coeff 0.2500

New in:  3.5.2.9 
Go to: Basic  Intermediate  Expert  Top
KERNEL_DIIS_CONV_CRITERIA
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] x : [HKS,SKH] commutator y : delta energy gap (in Hartree) z : delta energy: E(n+1)E(n) (in Hartree) 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:  1000 
Example:  kernel_diis_conv_criteria 0110 (activates x and y but not w or z)

New in:  3.5.2.9 
Go to: Basic  Intermediate  Expert  Top
KERNEL_DIIS_LINEAR_ITER
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:  5 
Example:  kernel_diis_linear_iter 10

New in:  3.5.2.9 
Go to: Basic  Intermediate  Expert  Top
KERNEL_DIIS_SIZE
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:  10 
Example:  kernel_diis_size 25

New in:  3.5.2.9 
Go to: Basic  Intermediate  Expert  Top
KERNEL_DIIS_MAXIT
Syntax:  KERNEL_DIIS_MAXIT [Integer]

Description:  Maximum number of inner loop DIIS iterations 
Default:  25 
Example:  kernel_diis_maxit 40

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
KERNEL_DIIS_THRESHOLD
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:  1.0e9 
Example:  kernel_diis_thres 1.0e7

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
KERNEL_DIIS_LSHIFT
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:  1.0 Hartree 
Example:  kernel_diis_lshift: 1 eV

New in:  3.5.2.9 
Go to: Basic  Intermediate  Expert  Top
KERNEL_DIIS_LS_ITER
Syntax:  KERNEL_DIIS_LS_ITER [Integer]

Description:  Number of iterations of the inner loop DIIS method with levelshifting enabled. 
Default:  0 
Example:  kernel_diis_ls_iter: 5

New in:  3.5.2.9 
Go to: Basic  Intermediate  Expert  Top
KERNEL_UPDATE
Syntax:  KERNEL_UPDATE [Logical]

Description:  Update the density kernel when taking a trial step for NGWF optimization. 
Default:  False 
Example:  kernel_update T

Go to: Basic  Intermediate  Expert  Top
KINETIC_INT_BATCH_SIZE
Syntax:  KINETIC_INT_BATCH_SIZE [Integer]

Description:  Specifies the number of NGWFs to communicate in a single batch during the evaluation of the kinetic energy integrals. May be used for tuning parallel performance, especially if "stack full" warnings are reported. 
Default:  10 
Example:  kinetic_int_batch_size 5

Go to: Basic  Intermediate  Expert  Top
K_ZERO
Syntax:  K_ZERO [Real]

Description:  Specifies the kinetic energy preconditioning parameter as an inverse length in atomic units (a01). See Mostofi et al.,J. Chem. Phys.119, 8842 (2003) for further details. 
Default:  3.0 
Example:  k_zero 4.0

Go to: Basic  Intermediate  Expert  Top
LATTICE_CART
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. 
Example: 

Go to: Basic  Intermediate  Expert  Top
LDOS_SMEAR
Syntax:  LDOS_SMEAR [Value] [Unit]

Description:  Specifies the Gaussian smearing for the local density of states calculated if properties are requested and species_ldos_groups has defined at least one LDOS group. If the smearing width is negative, the local density of states is not calculated.

Default:  0.1 eV 
Example:  ldos_smear 7 mRy

Go to: Basic  Intermediate  Expert  Top
LIBXC_X_FUNC_ID
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:  0 
Example:  libxc_x_func_id 13

Go to: Basic  Intermediate  Expert  Top
LIBXC_C_FUNC_ID
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:  0 
Example:  libxc_c_func_id 13

Go to: Basic  Intermediate  Expert  Top
LNV_CG_TYPE
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:  LNV_FLETCHER 
Example:  lnv_cg_type LNV_POLAK

Go to: Basic  Intermediate  Expert  Top
LNV_CG_MAX_STEP
Syntax:  LNV_CG_MAX_STEP [Value]

Description:  Maximum length of trial step for kernel optimisation line search 
Default:  2.0 
Example:  lnv_cg_max_step 10.0

Go to: Basic  Intermediate  Expert  Top
LNV_CHECK_TRIAL_STEPS
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:  F 
Example:  lnv_check_trial_steps T

Go to: Basic  Intermediate  Expert  Top
LNV_THRESHOLD_ORIG
Syntax:  LNV_THRESHOLD_ORIG [Real]

Description:  Specifies the convergence threshold for the RMS gradient of the density kernel. 
Default:  109 
Example:  lnv_threshold_orig 1.0e8

Go to: Basic  Intermediate  Expert  Top
LOCPOT_INT_BATCH_SIZE
Syntax:  LOCPOT_INT_BATCH_SIZE [Integer]

Description:  Specifies the number of NGWFs to communicate in a single batch during the evaluation of the local potential integrals. May be used for tuning parallel performance, especially if "stack full" warnings are reported. 
Default:  10 
Example:  locpot_int_batch_size 5

Go to: Basic  Intermediate  Expert  Top
LOCPOT_SCHEME
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:  FULL  
Example:  locpot_scheme ALTERNATE

Go to: Basic  Intermediate  Expert  Top
LUMO_DENS_PLOT
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:  5 ; plot the LUMO and the five canonical orbitals above 
Example:  lumo_dens_plot 0

Go to: Basic  Intermediate  Expert  Top
LUMO_PLOT
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:  5 ; plot the LUMO and the five canonical orbitals above 
Example:  lumo_plot 0

Go to: Basic  Intermediate  Expert  Top
MAXIT_HOTELLING
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:  50 
Example:  maxit_hotelling 100

Go to: Basic  Intermediate  Expert  Top
MAXIT_LNV
Syntax:  MAXIT_LNV [Integer]

Description:  Specifies the maximum number of iterations for the density kernel optimization. 
Default:  8 
Example:  maxit_lnv 3

Go to: Basic  Intermediate  Expert  Top
MAXIT_NGWF_CG
Syntax:  MAXIT_NGWF_CG [Integer]

Description:  Specifies the maximum number of iterations for the NGWF conjugate gradients optimization. 
Default:  100 
Example:  maxit_ngwf_cg 25

Go to: Basic  Intermediate  Expert  Top
MAXIT_PALSER_MANO
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:  50 
Example:  maxit_palser_mano 30

Go to: Basic  Intermediate  Expert  Top
MAXIT_PEN
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:  3 
Example:  maxit_pen 5

Go to: Basic  Intermediate  Expert  Top
MAX_RESID_HOTELLING
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:  1012 
Example:  max_resid_hotelling 1.0e10

Go to: Basic  Intermediate  Expert  Top
MD_DELTA_T
Syntax:  MD_DELTA_T [Value] [Unit]

Description:  Specifies the time step for molecular dynamics. 
Default:  40 aut ; 40 atomic units of time 
Example:  md_delta_t 1.0 fs

Go to: Basic  Intermediate  Expert  Top
MD_NUM_ITER
Syntax:  MD_NUM_ITER [Integer]

Description:  Specifies the number of molecular dynamics steps. 
Default:  100 
Example:  md_num_iter 1000

Go to: Basic  Intermediate  Expert  Top
MD_RESET_DKN_NGWFS
Syntax:  MD_RESET_DKN_NGWFS [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_DKN_NGWFS 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:  100 
Example:  md_reset_dkn_ngwfs 1000

Go to: Basic  Intermediate  Expert  Top
MD_RESTART
Syntax:  MD_RESTART [Logical]

Description:  Restart the molecular dynamics calculation from previously generated backup files (i.e. *.md.restart and *.thermo.restart files). 
Default:  False 
Example:  md_restart T

Go to: Basic  Intermediate  Expert  Top
MIX_DENSKERN_NUM
Syntax:  MIX_DENSKERN_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_DENSKERN_TYPE for a description of the available mixing schemes.

Default:  1 
Example:  mix_denskern_num 2

Go to: Basic  Intermediate  Expert  Top
MIX_DENSKERN_TYPE
Syntax:  MIX_DENSKERN_TYPE [Integer]

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:  1 
Example:  mix_denskern_type 2

Go to: Basic  Intermediate  Expert  Top
MIX_LOCAL_LENGTH
Syntax:  MIX_LOCAL_LENGTH [Value] [Unit]

Description:  Specifies the localization length required by MIX_NGWFS_TYPE =3.

Default:  10.0 bohr ; 
Example:  mix_local_length 15.0 bohr

Go to: Basic  Intermediate  Expert  Top
MIX_LOCAL_SMEAR
Syntax:  MIX_LOCAL_SMEAR [Value] [Unit]

Description:  Allows to smear out the localization sphere used when MIX_NGWFS_TYPE =3.

Default:  0.0 bohr ; 
Example:  mix_local_length 3.0 bohr

Go to: Basic  Intermediate  Expert  Top
MIX_NGWFS_NUM
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:  1 
Example:  mix_ngwfs_num 2

Go to: Basic  Intermediate  Expert  Top
MIX_NGWFS_TYPE
Syntax:  MIX_NGWFS_TYPE [Integer]

Description:  Specifies the mixing scheme used to generate new initial guesses for the NGWFs from the NGWFs optimized at previous MD steps.

Default:  1 
Example:  mix_ngwfs_type 2

Go to: Basic  Intermediate  Expert  Top
MINIT_LNV
Syntax:  MINIT_LNV [Integer]

Description:  Specifies the minimum number of iterations for the density kernel optimization. 
Default:  3 
Example:  minit_lnv 1

Go to: Basic  Intermediate  Expert  Top
NGWF_CG_TYPE
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:  NGWF_FLETCHER 
Example:  ngwf_cg_type NGWF_POLAK

Go to: Basic  Intermediate  Expert  Top
NGWF_CG_ROTATE
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:  False 
Example:  ngwf_cg_rotate T

Go to: Basic  Intermediate  Expert  Top
NGWF_CG_MAX_STEP
Syntax:  NGWF_CG_MAX_STEP [Value]

Description:  Maximum length of trial step for NGWF optimisation line search 
Default:  2.0 
Example:  ngwf_cg_max_step 10.0

Go to: Basic  Intermediate  Expert  Top
NGWF_GRAD_BATCH_SIZE
Syntax:  NGWF_GRAD_BATCH_SIZE [Integer]

Description:  Specifies the number of NGWFs to communicate in a single batch during the evaluation of the NGWF gradient. May be used for tuning parallel performance, especially if "stack full" warnings are reported. 
Default:  10 
Example:  ngwf_grad_batch_size 5

Go to: Basic  Intermediate  Expert  Top
NGWF_HALO
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:  1.0 ; no halo 
Example:  ngwf_halo 1.0

Go to: Basic  Intermediate  Expert  Top
NGWF_MAX_GRAD
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:  2 times 105 
Example:  ngwf_max_grad 1.0e4

Go to: Basic  Intermediate  Expert  Top
NGWF_THRESHOLD_ORIG
Syntax:  NGWF_THRESHOLD_ORIG [Real]

Description:  Specifies the convergence threshold for the RMS gradient of the NGWFs. 
Default:  2 times 106 
Example:  ngwf_threshold_orig 1.0e5

Go to: Basic  Intermediate  Expert  Top
NNHO
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:  False 
Example:  nnho T

Go to: Basic  Intermediate  Expert  Top
NONSC_FORCES
Syntax:  NONSC_FORCES [Logical]

Description:  Calculates the residual non selfconsistent forces due to the NGWF gradient. 
Default:  false 
Example:  nonsc_forces true

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
NUM_EIGENVALUES
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:  10 
Example:  num_eigenvalues 5

Go to: Basic  Intermediate  Expert  Top
OCC_MIX
Syntax:  OCC_MIX [Real]

Description:  Specifies the fraction of the NGWF gradient to which occupancy preconditioning is applied. 
Default:  0.25 
Example:  occ_mix 1.0 ; fully preconditioned gradient

Go to: Basic  Intermediate  Expert  Top
ODD_PSINC_GRID
Syntax:  ODD_PSINC_GRID [Logical]

Description:  Forces the simulation cell psinc grid to contain an odd number of points in each direction. 
Default:  False 
Example:  odd_osinc_grid T

Go to: Basic  Intermediate  Expert  Top
OLD_LNV
Syntax:  OLD_LNV [Logical]

Description:  Enables backwards compatibility with legacy code. 
Default:  False 
Example:  old_lnv T

Go to: Basic  Intermediate  Expert  Top
OPENBC_HARTREE
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:  F 
Example:  OPENBC_HARTREE T

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
OPENBC_ION_ION
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:  F 
Example:  OPENBC_ION_ION T

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
OPENBC_PSPOT
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:  F 
Example:  OPENBC_PSPOT T

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
OPENBC_PSPOT_FINETUNE_ALPHA
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:  0.3 
Example:  OPENBC_PSPOT_FINETUNE_ALPHA 0.5

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
OPENBC_PSPOT_FINETUNE_F
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:  1 
Example:  OPENBC_PSPOT_FINETUNE_F 6

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
OPENBC_PSPOT_FINETUNE_NPTSX
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:  100000 
Example:  OPENBC_PSPOT_FINETUNE_NPTS_X 500000

New in:  3.0.0 
Go to: Basic  Intermediate  Expert  Top
OUTPUT_DETAIL
Syntax:  OUTPUT_DETAIL [Text]

Description:  Specifies the level of detail in ONETEP's output: either BRIEF , NORMAL or VERBOSE .

Default:  NORMAL 
Example:  output_detail VERBOSE

Go to: Basic  Intermediate  Expert  Top
OVLP_FOR_NONLOCAL
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:  False 
Example:  ovlp_for_nonlocal T

Go to: Basic  Intermediate  Expert  Top
PADDED_LATTICE_CART
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. 
Example: 

Go to: Basic  Intermediate  Expert  Top
PAW
Syntax:  PAW [Logical]

Description:  Activates the Projector Augmented Wave Formalism: PAW potentials must then be supplied in the species_pot block.

Default:  False 
Example:  PAW : T

Go to: Basic  Intermediate  Expert  Top
PBC_CORRECTION_CUTOFF
Syntax:  PBC_CORRECTION_CUTOFF [Real]

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:  0.0 ; turned off 
Example:  pbc_correction_cutoff 7.0

New in:  2.4.9 
Go to: Basic  Intermediate  Expert  Top
PEN_PARAM
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:  4.0 
Example:  pen_param 5.0

Go to: Basic  Intermediate  Expert  Top
POLARISATION_CALCULATE
Syntax:  POLARISATION_CALCULATE [Logical]

Description:  Activates the calculation of polarisation 
Default:  False 
Example:  polarisation_calculate T

Go to: Basic  Intermediate  Expert  Top
POPN_BOND_CUTOFF
Syntax:  POPN_BOND_CUTOFF [Value] [Unit]

Description:  Specifies the bond length cutoff to use when performing Mulliken population analysis. 
Default:  3 Angstroms 
Example:  popn_bond_cutoff 5.0 ang

Go to: Basic  Intermediate  Expert  Top
POPN_CALCULATE
Syntax:  POPN_CALCULATE [Logical]

Description:  Perform Mulliken population analysis. 
Default:  True if DO_PROPERTIES is true, otherwise false.

Example:  popn_calculate F

Go to: Basic  Intermediate  Expert  Top
POSITIONS_ABS
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.

Example: 

Go to: Basic  Intermediate  Expert  Top
POSITIONS_ABS_INTERMEDIATE
Syntax:  See POSITIONS_ABS above.

Description:  Specifies the atomic positions as Cartesian coordinates in atomic units (a0) for the intermediate in a transition state search. 
Example:  See POSITIONS_ABS above.

Go to: Basic  Intermediate  Expert  Top
POSITIONS_ABS_PRODUCT
Syntax:  See POSITIONS_ABS above.

Description:  Specifies the atomic positions as Cartesian coordinates in atomic units (a0) for the product in a transition state search. 
Example:  See POSITIONS_ABS above.

Go to: Basic  Intermediate  Expert  Top
PPD_NPOINTS
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:  0 0 0 ; select automatically 
Example:  ppd_npoints 5 7 6

Go to: Basic  Intermediate  Expert  Top
PRECOND_REAL
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:  False 
Example:  precond_real T

Go to: Basic  Intermediate  Expert  Top
PRECOND_RECIP
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:  True 
Example:  precond_recip F

Go to: Basic  Intermediate  Expert  Top
PRECOND_SCHEME
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:  TETER 
Example:  precond_scheme MAURI

Go to: Basic  Intermediate  Expert  Top
PRINT_QC
Syntax:  PRINT_QC [Text]

Description:  Include a summary of the calculation in the output for the purposes of "quality control" on code modifications. 
Default:  False 
Example:  print_qc T

Go to: Basic  Intermediate  Expert  Top
PROJECTORS_PRECALCULATE
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:  True 
Example:  projectors_precalculate F

Go to: Basic  Intermediate  Expert  Top
PSINC_SPACING
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:  0.0 0.0 0.0 ; select automatically 
Example:  psinc_spacing 0.4 0.5 0.5
or 
Go to: Basic  Intermediate  Expert  Top
READ_DENSKERN
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:  False 
Example:  read_denskern T

Go to: Basic  Intermediate  Expert  Top
READ_HAMILTONIAN
Syntax:  READ_HAMILTONIAN [Logical]

Description:  Read the Hamiltonian matrix from a .ham file. Currently, only used for restarting EDFT calculations. 
Default:  F 
Example:  read_hamiltonian F

Go to: Basic  Intermediate  Expert  Top
READ_MAX_L
Syntax:  READ_MAX_L [Integer]

Description:  Specifies the maximum angular momentum of the spherical waves (l number) when reading from file. 
Default:  3 
Example:  read_max_l 5

Go to: Basic  Intermediate  Expert  Top
READ_SW_NGWFS
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:  False 
Example:  read_sw_ngwfs T

Go to: Basic  Intermediate  Expert  Top
READ_TIGHTBOX_NGWFS
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:  False 
Example:  read_tightbox_ngwfs T

Go to: Basic  Intermediate  Expert  Top
R_PRECOND
Syntax:  R_PRECOND [Real]

Description:  Specifies the radius in atomic units (a0) of the realspace kinetic energy preconditioner (used to accelerate the convolution). 
Default:  2.0 
Example:  r_precond 1.5

Go to: Basic  Intermediate  Expert  Top
SMOOTH_PROJECTORS
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:  0.4 ; no smoothing 
Example:  smooth_projectors 0.5

Go to: Basic  Intermediate  Expert  Top
SPECIES
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.

Example: 

Go to: Basic  Intermediate  Expert  Top
SPECIES_ATOMIC_SET
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:  SOLVE for all species when this block is absent

Example: 

Go to: Basic  Intermediate  Expert  Top
SPECIES_COND
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.

Example: 

Go to: Basic  Intermediate  Expert  Top
SPECIES_CONSTRAINTS
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.

Example: 

Go to: Basic  Intermediate  Expert  Top
SPECIES_LDOS_GROUPS
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 .

Example: 

Go to: Basic  Intermediate  Expert  Top
SPECIES_NGWF_PLOT
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.

Example: 

Go to: Basic  Intermediate  Expert  Top
SPECIES_POT
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.

Example: 

Go to: Basic  Intermediate  Expert  Top
SPIN
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. 
Default:  0 
Example:  spin 1

Go to: Basic  Intermediate  Expert  Top
SPIN_POLARIZED
Syntax:  SPIN_POLARIZED [Logical]

Description:  Specifies that a spinpolarized calculation should be performed. 
Default:  False, unless SPIN is nonzero, in which case true.

Example:  spin_polarized T

Go to: Basic  Intermediate  Expert  Top
SPREAD_CALCULATE
Syntax:  SPREAD_CALCULATE [Text]

Description:  Activates the Calculation of NGWF spreads 
Default:  F 
Example:  spread_calculate T

Go to: Basic  Intermediate  Expert  Top
TASK
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:  SINGLEPOINT 
Example:  task GEOMETRYOPTIMIZATION

Go to: Basic  Intermediate  Expert  Top
THERMOSTAT
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,

Example: 
In this example, the system is quenched from 3000 K using an ANDERSEN thermostat and then equilibrated by means of a NoseHoover chain. Here the value of the asymmetric stretching mode in water (0.053213/fs) has been used as the coupling frequency. %block thermostat 0001 1350 ANDERSEN 3000 K tgrad = 2 K 1351 5000 NOSEHOOVER 300 K nchain = 4 nstep = 8 freq = 0.053213 %endblock thermostat 
Go to: Basic  Intermediate  Expert  Top
TIMINGS_LEVEL
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:  1 
Example:  timings_level 0

Go to: Basic  Intermediate  Expert  Top
TSSEARCH_CG_MAX_ITER
Syntax:  TSSEARCH_CG_MAX_ITER [Integer]

Description:  Specifies the maximum number of conjugate gradients iterations for the transition state search. 
Default:  20 
Example:  tssearch_cg_max_iter 30

Go to: Basic  Intermediate  Expert  Top
TSSEARCH_DISP_TOL
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:  102a0 
Example:  tssearch_disp_tol 1.0e3 nm

Go to: Basic  Intermediate  Expert  Top
TSSEARCH_FORCE_TOL
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:  0.005 Ha/Bohr 
Example:  tssearch_force_tol 0.05 'ev/ang'

Go to: Basic  Intermediate  Expert  Top
TSSEARCH_METHOD
Syntax:  TSSEARCH_METHOD [Text]

Description:  Specifies the method for transition state search, currently only LSTQST .

Default:  LSTQST 
Example:  tssearch_method LSTQST

Go to: Basic  Intermediate  Expert  Top
TSSEARCH_LSTQST_PROTOCOL
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:  LSTMAXIMUM 
Example:  tssearch_lstqst_protocol LST/OPTIMIZATION

Go to: Basic  Intermediate  Expert  Top
TSSEARCH_QST_MAX_ITER
Syntax:  TSSEARCH_QST_MAX_ITER [Integer]

Description:  Specifies the maximum number of QST iterations for the transition state search. 
Default:  5 
Example:  tssearch_qst_max_iter 10

Go to: Basic  Intermediate  Expert  Top
USE_SPACE_FILLING_CURVE
Syntax:  USE_SPACE_FILLING_CURVE [Logical]

Description:  Use a Hilbert spacefilling curve to distribute the atoms among processors in a parallel calculation. 
Default:  True 
Example:  use_space_filling_curve F

Go to: Basic  Intermediate  Expert  Top
VERBOSE_EWALD_FORCES
Syntax:  VERBOSE_EWALD_FORCES [Logical]

Description:  Include details of the Ewald forces in the output. 
Default:  False 
Example:  verbose_ewald_forces T

Go to: Basic  Intermediate  Expert  Top
WRITE_CONVERGED_DKNGWFS
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:  F 
Example:  write_converged_dkngwfs T

Go to: Basic  Intermediate  Expert  Top
WRITE_DENSITY_PLOT
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:  True 
Example:  write_density_plot F

Go to: Basic  Intermediate  Expert  Top
WRITE_DENSKERN
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:  True 
Example:  write_denskern F

Go to: Basic  Intermediate  Expert  Top
WRITE_FORCES
Syntax:  WRITE_FORCES [Logical]

Description:  Include the forces in the output of a single point energy calculation. 
Default:  False 
Example:  write_forces T

Go to: Basic  Intermediate  Expert  Top
WRITE_HAMILTONIAN
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:  False 
Example:  write_hamiltonian T

Go to: Basic  Intermediate  Expert  Top
WRITE_MAX_L
Syntax:  WRITE_MAX_L [Integer]

Description:  Specifies the maximum angular momentum of the spherical waves (l number) when writing to file. 
Default:  3 
Example:  write_max_l 2

Go to: Basic  Intermediate  Expert  Top
WRITE_NGWF_PLOT
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:  False 
Example:  write_ngwf_plot T

Go to: Basic  Intermediate  Expert  Top
WRITE_SW_NGWFS
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:  False 
Example:  write_sw_ngwfs T

Go to: Basic  Intermediate  Expert  Top
WRITE_TIGHTBOX_NGWFS
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:  True 
Example:  write_tightbox_ngwfs F

Go to: Basic  Intermediate  Expert  Top
WRITE_XYZ
Syntax:  WRITE_XYZ [Logical]

Description:  Write the atom coordinates to disk as an .xyz file 
Default:  F 
Example:  write_xyz T

Go to: Basic  Intermediate  Expert  Top
XC_FUNCTIONAL
Syntax:  XC_FUNCTIONAL [Text]

Description:  Specifies the exchangecorrelation functional to use, currently one of:

Default:  LDA 
Example:  xc_functional PBE

Go to: Basic  Intermediate  Expert  Top
ZERO_TOTAL_FORCE
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:  True 
Example:  zero_total_force F

New in:  3.5.2.16 
Go to: Basic  Intermediate  Expert  Top