AMGGAX: Difference between revisions

Latest revision as of 14:00, 2 July 2024

AMGGAX = [real]

Default: AMGGAX	= 1.0-AEXX	if LHFCALC=.TRUE.
	= 1.0	if LHFCALC=.FALSE.

Description: AMGGAX is a parameter that multiplies the meta-GGA exchange functional (available as of VASP.6.4.0).

AMGGAX can be used as the fraction of meta-GGA exchange in a Hartree-Fock/DFT hybrid functional (possible since VASP.6.4.0).

Important: AMGGAX can be used only if LHFCALC=.TRUE.

Mind:

Note the difference with respect to AGGAX: AMGGAX multiplies the whole meta-GGA exchange functional, while AGGAX multiplies only the gradient-correction term of a GGA exchange functional.
AMGGAX is implemented for the functionals from Libxc (see LIBXC1 for details).

@@ Line 1: / Line 1: @@
-{{TAGDEF|AMGGAX|[real]|1.0-{{TAG|AEXX}}}}
+{{TAGDEF|AMGGAX|[real]}}
+{{DEF|AMGGAX|1.0-{{TAG|AEXX}} | if {{TAG|LHFCALC}}{{=}}.TRUE. | 1.0 | if {{TAG|LHFCALC}}{{=}}.FALSE.}}
-Description: {{TAG|AMGGAX}} specifies the fraction of meta-GGA exchange in a Hartree-Fock/meta-GGA hybrid functional type calculation.
+Description: {{TAG|AMGGAX}} is a parameter that multiplies the meta-GGA exchange functional (available as of VASP.6.4.0).
 ----
-The sum of the fraction of the exact exchange and LDA exchange is always 1.0, and it is not possible to set the amount of LDA exchange independently. Examples: if {{TAG|AEXX}}=0.25, 1/4 of the exact exchange is used, and 3/4 of the LDA exchange is added. For {{TAG|AEXX}}=0.5, half of the exact exchange is used, and one half of the LDA exchange is added.
+{{TAG|AMGGAX}} can be used as the fraction of meta-GGA exchange in a Hartree-Fock/DFT hybrid functional (possible since VASP.6.4.0).
+{{NB|important|{{TAG|AMGGAX}} can be used only if {{TAG|LHFCALC}}{{=}}.TRUE.}}
-The amount of LDA correlation included in the hybrid functional can be specified through the {{TAG|ALDAC}}-tag.
+{{NB|mind|
+*Note the difference with respect to {{TAG|AGGAX}}: {{TAG|AMGGAX}} multiplies the whole meta-GGA exchange functional, while {{TAG|AGGAX}} multiplies only the gradient-correction term of a GGA exchange functional.
-The amount of gradient correction to the exchange and the correlation contributions can be set indepently, however (some [[list_of_hybrid_functionals|popular hybride functionals]] for instance use only 0.8 of the gradient contribition to the exchange). The GGA flags {{TAG|AGGAX}} and {{TAG|AGGAC}} are only used if GGA is already selected (for LDA type calculations no gradient correction will be added regardless of values is used for {{TAG|AGGAX}} and {{TAG|AGGAC}}).
+*{{TAG|AMGGAX}} is implemented for the functionals from Libxc (see {{TAG|LIBXC1}} for details).}}
 == Related tags and articles ==
 {{TAG|AEXX}},
+{{TAG|ALDAX}},
+{{TAG|ALDAC}},
+{{TAG|AGGAX}},
 {{TAG|AGGAC}},
-{{TAG|ALDAC}},
+{{TAG|AMGGAC}},
 {{TAG|LHFCALC}},
-[[list_of_hybrid_functionals|List of hybrid functionals]]
+[[list_of_hybrid_functionals|List of hybrid functionals]],
+[[Hybrid_functionals:_formalism|Hybrid functionals: formalism]]
-{{sc|AGGAX|Examples|Examples that use this tag}}
+{{sc|AMGGAX|Examples|Examples that use this tag}}
 ----
 [[Category:INCAR tag]][[Category:Exchange-correlation functionals]][[Category:Hybrid_functionals]]