FIT Force Constants 3.48, by Axel van de Walle
-f Fit force constants (otherwise, generate pertubations) (Default: Off)
-si=[string] Input file defining the ideal structure (default: str.out)
-sr=[string] Input file defining the relaxed structure (default: str_relax.out)
-er=[real] Minimum distance between displaced atoms (Default: 0)
-ernn=[real] Minimum distance between displaced atoms in multiple of nearest neighbor distance
(Default: 0)
-fr=[real] Force constant range (Default: 0)
-frnn=[real] Force constant range (in multiple of nearest neighbor distance) (Default: 0)
-dr=[real] Displacement of the perturbed atom (default: 0.2)
-ms=[real] Strain of the maximum volume sampled (default: 0.01)
-dv Specified strain above is volumetric (Default: Off)
-ns=[int] Number of volume sample (default: 2)
-iu Include Unperturbed structure in generated structures (Default: Off)
-nrr Do not rerelax structures at each new volume (Default: Off)
-cs Check for Singular matrix in fit (Default: Off)
-ncs No check for singular matrix in fit (this is the default, option included for
backward compatibility) (Default: Off)
-wm Write fitting Matrices (Default: Off)
-sf=[string] Extra strain file (Default: )
-m=[string] Input file defining the atomic masses (default: ${atatdir}/data/masses.in)
-T0=[real] Minimum temperature (default: 0)
-T1=[real] Maximum temperature (default: 2000)
-dT=[real] Temperature step (default: 100)
-P=[real] Pressure (in GPa, default: 0)
-kp=[real] Number of k-points per reciprocal atom (default: 1000)
-kx=[int] k-point mesh (along 1st recip lat. vect.) if <>0 then overrides -kp=... (Default:
0)
-ky=[int] k-point mesh (along 2nd recip lat. vect.) (Default: 0)
-kz=[int] k-point mesh (along 3rd recip lat. vect.) (Default: 0)
-fp=[int] Power of polynomial to fit free energy (Default: -1)
-s0 Use a gamma-centered k-point mesh (default shift: 1/2 1/2 1/2) (Default: Off)
-sx=[real] k-point shift (along 1st recip lat. vect.) (Default: 0.5)
-sy=[real] k-point shift (along 2nd recip lat. vect.) (Default: 0.5)
-sz=[real] k-point shift (along 3rd recip lat. vect.) (Default: 0.5)
-df=[string] Phonon dispersion curve calculation input file. (Default: )
-hp=[real] Planck's constant (default in (eV s))
-kb=[real] Boltzman's constant (default in eV/K)
-cfk=[real] Conversion factor for force constants into energy/dist^2 (default: converts eV/A^2
into J/m^2)
-mu=[real] Mass units (default: converts a.u. mass into kg)
-rl=[real] Robust Length algorithm parameter for soft modes (beta) (Default: 0)
-rls=[real] Quadratic strain-dependence of robust length for positive strain (beta) (Default:
0)
-cP=[real] Conversion factor from pressure*volume into eV (Default: 0.00624151)
-pa Output free energy per atom instead of per unit cell (Default: Off)
-pe Print energy in 3rd column of fitfc.out (Default: Off)
-sc=[real] Correction factor if spectator ion are present (default: 1)
-me0 Subtract energy at 0K (Default: Off)
-no Print number of atom in supercell only (Default: Off)
-w1 Flag first perturbation wait1 instead of wait file (Default: Off)
-w2 Flag negative perturbation directions with wait2 instead of wait file (Default:
Off)
-fn Force continuation of calculations even if unstable (Default: Off)
-fu Find unstable modes (Default: Off)
-gu=[int] Generate unstable modes number n (Default: 0)
-gn Also Generate Negative displacements for mode specified by -gu=... (Default: Off)
-mau=[int] Maximum number of atom per supercell for unstable mode generation (Default: 64)
-sfc=[int] Simplify force constants: 1=streching+bending, 2=symmetric (Default: 0)
-apd Atom-Projected DOS (Default: Off)
-sig=[int] Number of significant digits printed (default: 5)
-z=[real] Tolerance for finding symmetry operations (default: 1e-3)
-h Display more help (Default: Off)
avdw@alum.mit.edu Wed, Dec 6, 2023 12:55:16 PM