LIBXC1 Pn: Difference between revisions

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{{TAGDEF|LIBXC1_Pn|[real]
{{TAGDEF|NUM_WANN|[integer]|{{TAG|NBANDS}}}}


Description: {{TAG|LIBXC1}} and [[LIBXC1|LIBXC2]] specify the functionals from the library of exchange-correlation functionals Libxc {{cite|marques:cpc:2012}}{{cite|lehtola:sx:2018}} that one wants to use.
Description: Since vasp 6.2.0 {{TAG|NUM_WANN}} determines the number of Wannier orbitals to be used with wannier90. Note that the <code>num_wann</code> value written to the <code>wannier90.win</code> file is always the value of {{TAG|NUM_WANN}} known by vasp.
 
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{{TAG|LIBXC1}} and [[LIBXC1|LIBXC2]] can be either integers or strings. The available functionals are listed on the Libxc website<ref name="libxc"/> 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 {{TAG|LIBXC1}} and [[LIBXC1|LIBXC2]] are the following:
 
*Both {{TAGDEF|LIBXC1}} and [[LIBXC1|LIBXC2]] are specified and correspond to the exchange and correlation functionals, respectively, or vice versa.
*Only {{TAGDEF|LIBXC1}} (or [[LIBXC1|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 {{TAG|GGA}} = LIBXC for LDA, GGA and GGA-based hybrid functionals or {{TAG|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 {{TAG|LIBXC1_Pn}} and {{TAG|LIBXC2_Pn}}, where ''n=1, 2, ...'' in {{FILE|INCAR}}.
 
Examples of how to specify a Libxc functional in {{FILE|INCAR}} are given below for the GGA PBE{{cite|perdew:prl:1996}}, meta-GGA SCAN{{cite|sun:prl:15}} and hybrid PBEh (PBE0){{cite|adamo:jcp:1999}} functionals.
 
*PBE
{{TAG|GGA}} = LIBXC
{{TAG|LIBXC1}} = 101
[[LIBXC1|LIBXC2]] = 130
or
{{TAG|GGA}} = LIBXC
{{TAG|LIBXC1}} = GGA_X_PBE
[[LIBXC1|LIBXC2]] = GGA_C_PBE
 
*SCAN
{{TAG|METAGGA}} = LIBXC
{{TAG|LIBXC1}} = 263
[[LIBXC1|LIBXC2]] = 267
or
{{TAG|METAGGA}} = LIBXC
{{TAG|LIBXC1}} = MGGA_X_SCAN
[[LIBXC1|LIBXC2]] = MGGA_C_SCAN
 
*PBEh (PBE0)
{{TAG|LHFCALC}} = .TRUE.
{{TAG|AEXX}} = 0.25
{{TAG|GGA}} = LIBXC
{{TAG|LIBXC1}} = 406
or
{{TAG|LHFCALC}} = .TRUE.
{{TAG|AEXX}} = 0.25
{{TAG|GGA}} = LIBXC
{{TAG|LIBXC1}} = HYB_GGA_XC_PBEH
 
<references>
<ref name="libxc">https://www.tddft.org/programs/libxc/]</ref>
</references>


== Related Tags and Sections ==
== Related Tags and Sections ==
{{TAG|AGGAX}},
{{TAG|LWANNIER90}},
{{TAG|AGGAC}},
{{TAG|LWRITE_UNK}},
{{TAG|ALDAC}},
{{TAG|LWRITE_MMN_AMN}},
{{TAG|LHFCALC}},
{{TAG|LWANNIER90_RUN}}
[[Hartree-Fock_and_HF/DFT_hybrid_functionals|hybrid functionals]],
[[specific_hybrid_functionals|settings for specific hybrid functionals]]
 
{{sc|AEXX|Examples|Examples that use this tag}}
 
----
----


[[Category:INCAR]][[Category:XC Functionals]][[Category:Hybrids]]
[[Category:INCAR]][[Category:Wannier Functions]]

Revision as of 13:02, 5 January 2022

NUM_WANN = [integer]
Default: NUM_WANN = NBANDS 

Description: Since vasp 6.2.0 NUM_WANN determines the number of Wannier orbitals to be used with wannier90. Note that the num_wann value written to the wannier90.win file is always the value of NUM_WANN known by vasp.

Related Tags and Sections

LWANNIER90, LWRITE_UNK, LWRITE_MMN_AMN, LWANNIER90_RUN