XC
XC = Combination of functionals
Description: XC specifies a LDA, GGA exchange-correlation functional.
This tag was added to perform GGA calculations with pseudopotentials generated with conventional LDA reference configurations.
| Important: VASP recalculates the exchange-correlation energy inside the PAW sphere and corrects the atomic energies given by the POTCAR file. For this to work, the original LEXCH tag must not be modified in the POTCAR file. |
A few points should be noted:
- The LIBXC option (or just LI) allows to use a LDA or GGA functional from the library of exchange-correlation functionals Libxc[1][2][3]. Along with GGA=LIBXC, it is also necessary to specify the LIBXC1 and LIBXC2 tags that specify the particular functional. Note that it is necessary to have Libxc >= 5.2.0 installed and VASP.6.3.0 or higher compiled with precompiler options.
- When the OR, BO, MK, ML or CX GGA is used in combination with the nonlocal vdW-DF functional of Dion et al.[4], the GGA component of the correlation should in principle be turned off with AGGAC=0 (see nonlocal vdW-DF functionals).
The possible options for the GGA tag are:
Related tags and articles
LIBXC1, LIBXC2, ALDAX, ALDAC, AGGAX, AGGAC, METAGGA
References
- ↑ 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://libxc.gitlab.io
- ↑ M. Dion, H. Rydberg, E. Schröder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004).