LIBXC1 Pn: Difference between revisions

Revision as of 12:08, 7 January 2022

Description: LIBXC1_Pn and LIBXC2_Pn, where $n=1, 2, ...$ allow to specify the values of the parameters of the functionals implemented in Libxc that are called with LIBXC1 and LIBXC2, respectively.

For many functionals implemented in the library of exchange-correlation functionals Libxc ^[1]^[2] it is possible to modify the parameters if one does not want to use the default values. If a functional from Libxc has parameters that can be modified, then they are listed in OUTCAR below "Parameters of Libxc functionals:" as P $n$ ( $n=1, 2, ...$ ).

An example is given below for the GGA PBE functional^[3] where the parameters $\mu=0.21951$ in exchange and $\beta=0.066725$ in correlation are changed to $\mu=10/81\approx0.12345679$ and $\beta=0.046$ to get the PBEsol functional^[4] (of course, the simpler way to use PBEsol from Libxc is to call it directly with LIBXC1=116 and LIBXC2=133).

GGA = LIBXC
LIBXC1 = 101
LIBXC2 = 130
LIBXC1_P2 = 0.12345679
LIBXC2_P1 = 0.046

Concerning the parameters of the semilocal component of hybrid functionals, whose tag contains HYB on the Libxc website^[5], the following should be noted.

The mixing parameter between the semilocal and exact exchange is one of the parameters LIBXC1_Pn, and can therefore be modified.
For HYB_GGA_XC_PBEH, HYB_GGA_XC_B1WC, HYB_GGA_XC_HSE03, HYB_GGA_XC_HSE06, HYB_GGA_XC_HSE12, and HYB_GGA_XC_HSE12S, the value of AEXX will be used and automatically passed to the corresponding parameter in Libxc. However, if this corresponding parameter (LIBXC1_Pn) is specified in INCAR, then AEXX will be overruled by LIBXC1_Pn.

Related Tags and Sections

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

Examples that use this tag

[marques:cpc:2012-1] M. A. L. Marques, M. J. T. Oliveira, and T. Burnus, Comput. Phys. Commun., 183, 2272 (2012).

[lehtola:sx:2018-2] S. Lehtola, C. Steigemann, M. J. T. Oliveira, and M. A. L. Marques, SoftwareX, 7, 1 (2018).

[perdew:prl:1996-3] J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett., 77, 3865 (1996).

[perdew:prl:2008-4] J. P. Perdew, A. Ruzsinszky, G. I. Csonka, O. A. Vydrov, G. E. Scuseria, L. A. Constantin, X. Zhou, and K. Burke, Phys. Rev. Lett. 100, 136406 (2008).

[libxc-5] ttps://libxc.gitlab.io

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 For many functionals implemented in the library of exchange-correlation functionals Libxc {{cite|marques:cpc:2012}}{{cite|lehtola:sx:2018}} it is possible to modify the parameters if one does not want to use the default values. If a functional from Libxc has parameters that can be modified, then they are listed in {{FILE|OUTCAR}} below "Parameters of Libxc functionals:" as P<math>n</math> (<math>n=1, 2, ...</math>).
-An example is given below for the GGA PBE functional{{cite|perdew:prl:1996}} where the parameters <math>\mu=0.21951</math> in exchange and <math>\beta=0.066725</math> in correlation are changed to <math>\mu=10/81\sim0.12345679</math> and <math>\beta=0.046</math> to get the PBEsol functional{{cite|perdew:prl:2008}} (of course, the simpler way to use PBEsol from Libxc is to call it directly with {{TAG|LIBXC1}}=116 and {{TAG|LIBXC2}}=133).
+An example is given below for the GGA PBE functional{{cite|perdew:prl:1996}} where the parameters <math>\mu=0.21951</math> in exchange and <math>\beta=0.066725</math> in correlation are changed to <math>\mu=10/81\approx0.12345679</math> and <math>\beta=0.046</math> to get the PBEsol functional{{cite|perdew:prl:2008}} (of course, the simpler way to use PBEsol from Libxc is to call it directly with {{TAG|LIBXC1}}=116 and {{TAG|LIBXC2}}=133).
   {{TAG|GGA}} = LIBXC
   {{TAG|LIBXC1}} = 101