XCm Pn - Revision history

Ftran at 21:46, 8 March 2026

2026-03-08T21:46:03Z

← Older revision		Revision as of 21:46, 8 March 2026
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	* Functionals in Libxc:		* Functionals in Libxc:
	:For many of the functionals implemented in the library of exchange-correlation functionals Libxc{{cite\|marques:cpc:2012}}{{cite\|lehtola:sx:2018}}{{cite\|libxc}} it is possible to modify the parameters. If a functional from Libxc has modifiable parameters, then they are listed in {{FILE\|OUTCAR}} below "Parameters of Libxc functionals:" as P<math>n</math> (<math>n=1, 2, \ldots</math>). Note that {{TAG\|LIBXC1_Pn}} and {{TAG\|LIBXC2_Pn}} are equivalent to {{TAG\|XCm_Pn}} when the functional is set with the tag {{TAG\|GGA}} or {{TAG\|METAGGA}}.		:For many of the functionals implemented in the library of exchange-correlation functionals Libxc{{cite\|marques:cpc:2012}}{{cite\|lehtola:sx:2018}}{{cite\|tran:arxiv:2026}}{{cite\|libxc}} it is possible to modify the parameters. If a functional from Libxc has modifiable parameters, then they are listed in {{FILE\|OUTCAR}} below "Parameters of Libxc functionals:" as P<math>n</math> (<math>n=1, 2, \ldots</math>). Note that {{TAG\|LIBXC1_Pn}} and {{TAG\|LIBXC2_Pn}} are equivalent to {{TAG\|XCm_Pn}} when the functional is set with the tag {{TAG\|GGA}} or {{TAG\|METAGGA}}.

	More information about the mixing and screening parameters in hybrid functionals can be found at {{TAG\|LIBXC1_Pn}}.		More information about the mixing and screening parameters in hybrid functionals can be found at {{TAG\|LIBXC1_Pn}}.

Ftran at 10:21, 2 March 2026

2026-03-02T10:21:12Z

← Older revision		Revision as of 10:21, 2 March 2026
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	[[XCm_Pn\|XC2_P1]] = 0.046 #parameter beta, which is the 1st parameter in GGA_C_PBE		[[XCm_Pn\|XC2_P1]] = 0.046 #parameter beta, which is the 1st parameter in GGA_C_PBE

	* In the MGGA MS1 functional~~{{cite\|sun:jcp:13}}~~ the default parameters <math>\kappa=0.404</math>, <math>c=0.18150</math> and <math>b=1.0</math> in exchange are changed to <math>\kappa=0.504</math>, <math>c=0.14601</math> and <math>b=4.0</math> to get the MS2 functional.~~{{cite\|sun:jcp:13}}~~		* In the MGGA MS1 functional the default parameters <math>\kappa=0.404</math>, <math>c=0.18150</math> and <math>b=1.0</math> in exchange (see Table I in Ref. {{cite\|sun:jcp:13}}) are changed to <math>\kappa=0.504</math>, <math>c=0.14601</math> and <math>b=4.0</math> to get the MS2 functional.
	{{TAG\|XC}} = MS1		{{TAG\|XC}} = MS1
	[[XCm_Pn\|XC1_P1]] = 0.504 #parameter kappa, which is the 1st parameter in MS0, MS1, and MS2		[[XCm_Pn\|XC1_P1]] = 0.504 #parameter kappa, which is the 1st parameter in MS0, MS1, and MS2
	[[XCm_Pn\|XC1_P2]] = 0.14601 #parameter c, which is the 2nd parameter in MS0, MS1, and MS2		[[XCm_Pn\|XC1_P2]] = 0.14601 #parameter c, which is the 2nd parameter in MS0, MS1, and MS2
	[[XCm_Pn\|XC1_P3]] = 4 #parameter b, which is the 3rd parameter in MS0, MS1, and MS2		[[XCm_Pn\|XC1_P3]] = 4.0 #parameter b, which is the 3rd parameter in MS0, MS1, and MS2

	== Related tags and articles ==		== Related tags and articles ==

Ftran at 15:20, 27 February 2026

2026-02-27T15:20:43Z

← Older revision		Revision as of 15:20, 27 February 2026
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	More information about the mixing and screening parameters in hybrid functionals can be found at {{TAG\|LIBXC1_Pn}}.		More information about the mixing and screening parameters in hybrid functionals can be found at {{TAG\|LIBXC1_Pn}}.
			{{NB\|mind\|{{TAG\|XCm_Pn}} is available since VASP.6.4.3.}}

	=== Examples ===		=== Examples ===

Ftran: Created page with "{{DISPLAYTITLE:XCm_Pn}} {{TAGDEF|XCm_Pn|[real]}} Description: {{TAG|XCm_Pn}}, where $m=1, 2, \ldots$ and $n=1, 2, \ldots$ allows to modify the parameters in a semilocal functional. ---- The {{TAG|XCm_Pn}} tag allows to modify the parameters in the semilocal functional set with the {{TAG|XC}} tag. In {{TAG|XCm_Pn}}, $m=1, 2, \ldots$ refers to the $m$ th component of the functional and $n=1, 2, \ldots$ to the $n<..."$

2026-02-27T15:09:17Z

Created page with "{{DISPLAYTITLE:XCm_Pn}} {{TAGDEF|XCm_Pn|[real]}} Description: {{TAG|XCm_Pn}}, where <math>m=1, 2, \ldots</math> and <math>n=1, 2, \ldots</math> allows to modify the parameters in a semilocal functional. ---- The {{TAG|XCm_Pn}} tag allows to modify the parameters in the semilocal functional set with the {{TAG|XC}} tag. In {{TAG|XCm_Pn}}, <math>m=1, 2, \ldots</math> refers to the <math>m</math>th component of the functional and <math>n=1, 2, \ldots</math> to the <math>n<..."

New page

{{DISPLAYTITLE:XCm_Pn}}
{{TAGDEF|XCm_Pn|[real]}}

Description: {{TAG|XCm_Pn}}, where <math>m=1, 2, \ldots</math> and <math>n=1, 2, \ldots</math> allows to modify the parameters in a semilocal functional.
----

The {{TAG|XCm_Pn}} tag allows to modify the parameters in the semilocal functional set with the {{TAG|XC}} tag. In {{TAG|XCm_Pn}}, <math>m=1, 2, \ldots</math> refers to the <math>m</math>th component of the functional and <math>n=1, 2, \ldots</math> to the <math>n</math>th parameter of this <math>m</math>th functional component.

The {{TAG|XCm_Pn}} tag can be used for functionals that are implemented in VASP or in Libxc.
* Functionals in VASP:
: The number of functionals with modifiable parameters is for the moment very limited and concerns only a few MGGAs. Among the functionals listed at {{TAG|METAGGA}}, there is MS0, MS1, and MS2,{{cite|sun:jcp:12}}{{cite|sun:jcp:13}} for instance. The functionals with modifiable parameters can be found by searching for "XC%PARAM" in the subroutine SET_XC_DATA in the setex.F file.

* Functionals in Libxc:
:For many of the functionals implemented in the library of exchange-correlation functionals Libxc{{cite|marques:cpc:2012}}{{cite|lehtola:sx:2018}}{{cite|libxc}} it is possible to modify the parameters. If a functional from Libxc has modifiable parameters, then they are listed in {{FILE|OUTCAR}} below "Parameters of Libxc functionals:" as P<math>n</math> (<math>n=1, 2, \ldots</math>). Note that {{TAG|LIBXC1_Pn}} and {{TAG|LIBXC2_Pn}} are equivalent to {{TAG|XCm_Pn}} when the functional is set with the tag {{TAG|GGA}} or {{TAG|METAGGA}}.

More information about the mixing and screening parameters in hybrid functionals can be found at {{TAG|LIBXC1_Pn}}.

=== Examples ===

* In the GGA PBE functional,{{cite|perdew:prl:1996}} as implemented in Libxc, the default 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 would be to call it directly with "{{TAG|XC}}=GGA_X_PBE_SOL GGA_C_PBE_SOL"). This example is equivalent to the one given for {{TAG|LIBXC1_Pn}}.
{{TAG|XC}} = GGA_X_PBE GGA_C_PBE
[[XCm_Pn|XC1_P2]] = 0.12345679 #parameter mu, which is the 2nd parameter in GGA_X_PBE
[[XCm_Pn|XC2_P1]] = 0.046 #parameter beta, which is the 1st parameter in GGA_C_PBE

* In the MGGA MS1 functional{{cite|sun:jcp:13}} the default parameters <math>\kappa=0.404</math>, <math>c=0.18150</math> and <math>b=1.0</math> in exchange are changed to <math>\kappa=0.504</math>, <math>c=0.14601</math> and <math>b=4.0</math> to get the MS2 functional.{{cite|sun:jcp:13}}
{{TAG|XC}} = MS1
[[XCm_Pn|XC1_P1]] = 0.504 #parameter kappa, which is the 1st parameter in MS0, MS1, and MS2
[[XCm_Pn|XC1_P2]] = 0.14601 #parameter c, which is the 2nd parameter in MS0, MS1, and MS2
[[XCm_Pn|XC1_P3]] = 4 #parameter b, which is the 3rd parameter in MS0, MS1, and MS2

== Related tags and articles ==
{{TAG|XC}},
{{TAG|XC_C}},
{{TAG|GGA}},
{{TAG|METAGGA}},
{{TAG|LIBXC1}},
{{TAG|LIBXC2}},
{{TAG|LIBXC1_Pn}},
{{TAG|LIBXC2_Pn}}

== References ==
<references/>

----

[[Category:INCAR tag]][[Category:Exchange-correlation functionals]][[Category:Hybrid_functionals]]