LIBXC1 Pn
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 vice versa.
- 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).
In addition, many of the functionals implemented in Libxc have parameters that can be modified. This can be done with the tags LIBXC1_Pn and LIBXC2_Pn, where n=1, 2, ... in INCAR.
Examples of how to specify a Libxc functional in INCAR are given below for the GGA PBE[4], meta-GGA SCAN[5] and hybrid 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
- ↑ M. A. L. Marques, M. J. T. Oliveira, and T. Burnus, Comput. Phys. Commun., 183, 2272 (2012).
- ↑ S. Lehtola, C. Steigemann, M. J. T. Oliveira, and M. A. L. Marques, SoftwareX, 7, 1 (2018).
- ↑ https://www.tddft.org/programs/libxc/]
- ↑ J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett., 77, 3865 (1996).
- ↑ J. Sun, A. Ruzsinszky, and J. P. Perdew, Phys. Rev. Lett. 115, 036402 (2015).
- ↑ C. Adamo and V. Barone, Phys. Rev. Lett., 110, 6158 (1999).
Related Tags and Sections
AGGAX, AGGAC, ALDAC, LHFCALC, hybrid functionals, settings for specific hybrid functionals