LIBXC1

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Revision as of 10:10, 28 December 2021 by Ftran (talk | contribs)

LIBXC1 = [integer] or [string] 

Description: LIBXC1 and LIBXC2 specify the functionals from the library of exchange-correlation functionals Libxc [1][2] that one wants to use.


LIBXC1 and LIBXC2 can be either integers or strings. The available functionals are listed on the Libxc website[3] along with their associated tag and number (e.g., GGA_X_PBE and 101 for PBE exchange). The tag indicates if this is an exchange (X), correlation (C) or exchange-correlation (XC) functional, and to which family it belongs to, namely LDA (LDA or HYB_LDA), GGA (GGA or HYB_GGA) or meta-GGA (MGGA or HYB_MGGA).

The possibilities for LIBXC1 and LIBXC2 are the following:

  • Both LIBXC1  and LIBXC2 are specified and correspond to the exchange and correlation functionals, respectively, or the reverse.
  • Only LIBXC1  (or LIBXC2) is specified and corresponds to an exchange or exchange-correlation functional. It can also be a correlation functional, but such a calculation without exchange would not make sense.

One has to specify also GGA = LIBXC for LDA, GGA and GGA-based hybrid functionals or METAGGA = LIBXC for meta-GGA functionals (hybrid-based meta-GGA functionals are not yet available in VASP).

Examples of how to specify a Libxc functional in INCAR are given below for the PBE[4], SCAN[5] and PBEh (PBE0)[6] functionals.

  • PBE
GGA = LIBXC
LIBXC1 = 101
LIBXC2 = 130

or

GGA = LIBXC
LIBXC1 = GGA_X_PBE
LIBXC2 = GGA_C_PBE
  • SCAN
METAGGA = LIBXC
LIBXC1 = 263
LIBXC2 = 267

or

METAGGA = LIBXC
LIBXC1 = MGGA_X_SCAN
LIBXC2 = MGGA_C_SCAN
  • PBEh (PBE0)
LHFCALC = .TRUE.
AEXX = 0.25
GGA = LIBXC
LIBXC1 = 406

or

LHFCALC = .TRUE.
AEXX = 0.25
GGA = LIBXC
LIBXC1 = HYB_GGA_XC_PBEH

Related Tags and Sections

AGGAX, AGGAC, ALDAC, LHFCALC, hybrid functionals, settings for specific hybrid functionals

Examples that use this tag