Exchange–correlation functionals

Exchange–correlation functionals#

The LibXC library is used for the evaluation of exchange–correlation functionals [LSOM18].

Available functionals#

The density functionals provided in the VeloxChem library can be listed with the available_functionals method.

import veloxchem as vlx

avail_funcs = vlx.available_functionals()

print('Available functionals:\n')

for i in range(0, len(avail_funcs), 8):
    print(', '.join(avail_funcs[i:i + 8]))

Available functionals:

SLATER, SLDA, B88X, BLYP, B3LYP, BHANDH, BHANDHLYP, PBE
PBE0, REVPBE, BP86, PW91, MPW1K, OLYP, O3LYP, X3LYP
B97, B97-1, B97-2, B97-3, LRC-WPBEH, CAM-B3LYP, TPSS, TPSSH
REVTPSS, PKZB, SCAN, RSCAN, R2SCAN, M05, M05-2X, M06
M06-2X, M06-HF, M06-L, M11-L, MPW1B95, MPWB1K, PW6B95, PWB6K

More functionals are being implemented and range-separated hybrids are a priority.

DFT settings#

Python script

The choice of functional is made by an attribute setting of SCF driver objects:

scf_drv.xcfun = "b3lyp"

Text file

The choice of functional is specified under method settings:

@method settings
xcfun: b3lyp
@end

Note

  • To change to another functional, replace b3lyp with any of the others (as spelled in the list above).

  • The grid level for numerical integrations will be auto-determined for a given functional.

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