PHON G CUTOFF - Revision history

Miranda.henrique at 10:36, 23 October 2023

2023-10-23T10:36:09Z

← Older revision		Revision as of 10:36, 23 October 2023
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	For more information on polar phonon calculations, see {{TAG\|LPHON_POLAR}}.		For more information on polar phonon calculations, see {{TAG\|LPHON_POLAR}}.

	{{NB\|mind\| Only available as of VASP 6.3.2.}}		{{NB\|mind\| Only available as of VASP 6.3.2.}}

Mani: Update the description and default value

2023-08-16T07:57:05Z

Update the description and default value

← Older revision		Revision as of 07:57, 16 August 2023
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	{{DISPLAYTITLE:PHON_G_CUTOFF}}		{{DISPLAYTITLE:PHON_G_CUTOFF}}
	{{TAGDEF\|PHON_G_CUTOFF\| [real] }}		{{TAGDEF\|PHON_G_CUTOFF\| [real] }}
	{{DEF\|PHON_G_CUTOFF\|~~None~~\|}}		{{DEF\|PHON_G_CUTOFF\|8.0\|}}

	Description: {{TAG\|PHON_G_CUTOFF}} sets the cutoff radius in reciprocal space used to determine the number of <math>\mathbf{G}</math> vectors involved in the Ewald sum in polar phonon calculations.		Description: {{TAG\|PHON_G_CUTOFF}} sets the cutoff radius in reciprocal space used to determine the number of <math>\mathbf{G}</math> vectors involved in the Ewald sum in polar phonon calculations.
	----		----

	~~If the material is polar (i.e. has more than one atom type), a special treatment of~~ the long-range ~~dipole~~-~~dipole interaction is required to obtain~~ a ~~smooth phonon dispersion~~.		The Ewald sum that accounts for the long-range electrostatic interactions in phonon calculations runs over all G-vectors inside a cutoff sphere.
	~~This~~ is ~~activated~~ by ~~setting~~ {{TAG\|~~LPHON_POLAR~~}}~~=.TRUE. and supplying~~ the ~~static dielectric tensor~~ (~~{{TAG\|PHON_DIELECTRIC}}~~) ~~and~~ the ~~Born-effective charges~~ (~~{{TAG\|PHON_BORN_CHARGES}}~~) ~~which can be obtained in~~ a ~~separate VASP calculation using the~~ {{TAG\|~~LEPSILON~~}} or {{TAG\|~~LCALCEPS~~}} ~~tag~~. ~~The long-range part~~ is ~~evaluated using an Ewald sum with~~ the ~~number of <math>\mathbf{G}</math> vectors in reciprocal space being determined using a cutoff length (~~{{TAG\|~~PHON_G_CUTOFF~~}}).		The radius of this sphere is given by {{TAG\|PHON_G_CUTOFF}} as a multiple of the longest reciprocal lattice vector of the primitive cell (as detected by VASP).
			Specifying the cutoff this way (as opposed to an absolute length or energy) ensures a default value that is relatively system-independent.

			The default value of {{TAG\|PHON_G_CUTOFF}} is a safe choice in most cases.
			Lowering {{TAG\|PHON_G_CUTOFF}} can result in faster phonon calculations.
			However, ensure that the phonon spectrum is properly converged.
			If you run into convergence problems, try raising the value until the phonon dispersion converges.

			For more information on polar phonon calculations, see {{TAG\|LPHON_POLAR}}.

	{{NB\|mind\| Only available as of VASP 6.3.2.}}		{{NB\|mind\| Only available as of VASP 6.3.2.}}

Miranda.henrique at 14:49, 10 August 2022

2022-08-10T14:49:08Z

← Older revision		Revision as of 14:49, 10 August 2022
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	{{DISPLAYTITLE:PHON_G_CUTOFF}}		{{DISPLAYTITLE:PHON_G_CUTOFF}}
	{{TAGDEF\|PHON_G_CUTOFF\| [~~3x3xNIONS~~ real] }}		{{TAGDEF\|PHON_G_CUTOFF\| [real] }}
	{{DEF\|PHON_G_CUTOFF\|None\|}}		{{DEF\|PHON_G_CUTOFF\|None\|}}

Tal at 09:40, 20 July 2022

2022-07-20T09:40:59Z

← Older revision		Revision as of 09:40, 20 July 2022
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	{{DEF\|PHON_G_CUTOFF\|None\|}}		{{DEF\|PHON_G_CUTOFF\|None\|}}

	Description: {{TAG\|PHON_G_CUTOFF}} sets the cutoff radius in reciprocal space used to determine the number of G-vectors involved in the Ewald sum in polar phonon calculations.		Description: {{TAG\|PHON_G_CUTOFF}} sets the cutoff radius in reciprocal space used to determine the number of <math>\mathbf{G}</math> vectors involved in the Ewald sum in polar phonon calculations.
	----		----

	If the material is polar (i.e. has more than one ~~different~~ atom type) a special treatment of the long-range dipole-dipole interaction is required to obtain a smooth phonon dispersion.		If the material is polar (i.e. has more than one atom type), a special treatment of the long-range dipole-dipole interaction is required to obtain a smooth phonon dispersion.
	This is activated by setting {{TAG\|LPHON_POLAR}}=.TRUE. and supplying the static dielectric tensor ({{TAG\|PHON_DIELECTRIC}}) and the Born-effective charges ({{TAG\|PHON_BORN_CHARGES}}) which can be obtained on a separate VASP ~~run~~ using the {{TAG\|LEPSILON}} or {{TAG\|LCALCEPS}} tag. The long-range part is evaluated using an Ewald sum with the number of G-vectors in reciprocal space being determined using a cutoff length ({{TAG\|PHON_G_CUTOFF}}).		This is activated by setting {{TAG\|LPHON_POLAR}}=.TRUE. and supplying the static dielectric tensor ({{TAG\|PHON_DIELECTRIC}}) and the Born-effective charges ({{TAG\|PHON_BORN_CHARGES}}) which can be obtained in a separate VASP calculation using the {{TAG\|LEPSILON}} or {{TAG\|LCALCEPS}} tag. The long-range part is evaluated using an Ewald sum with the number of <math>\mathbf{G}</math> vectors in reciprocal space being determined using a cutoff length ({{TAG\|PHON_G_CUTOFF}}).
	{{NB\|mind\| Only available as of VASP 6.3.2.}}		{{NB\|mind\| Only available as of VASP 6.3.2.}}

Miranda.henrique at 08:23, 20 July 2022

2022-07-20T08:23:44Z

← Older revision		Revision as of 08:23, 20 July 2022
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	{{TAG \| LPHON_POLAR}},		{{TAG \| LPHON_POLAR}},
	{{TAG \| PHON_DIELECTRIC}},		{{TAG \| PHON_DIELECTRIC}},
	{{TAG \| PHON_BORN_CHARGES~~}},~~		{{TAG \| PHON_BORN_CHARGES}}
	~~{{TAG \| PHON_DOS}},~~
	~~{{TAG \| PHON_SIGMA}},~~
	~~{{TAG \| PHON_NEDOS~~}}

	{{sc\|PHON_G_CUTOFF\|Examples\|Examples that use this tag}}		{{sc\|PHON_G_CUTOFF\|Examples\|Examples that use this tag}}

	[[Category:INCAR tag]][[Category:Phonons]]		[[Category:INCAR tag]][[Category:Phonons]]

Miranda.henrique at 08:23, 20 July 2022

2022-07-20T08:23:33Z

← Older revision		Revision as of 08:23, 20 July 2022
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			{{DISPLAYTITLE:PHON_G_CUTOFF}}
	{{TAGDEF\|PHON_G_CUTOFF\| [3x3xNIONS real] }}		{{TAGDEF\|PHON_G_CUTOFF\| [3x3xNIONS real] }}
	{{DEF\|PHON_G_CUTOFF\|None\|}}		{{DEF\|PHON_G_CUTOFF\|None\|}}
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	{{TAG \| PHON_DIELECTRIC}},		{{TAG \| PHON_DIELECTRIC}},
	{{TAG \| PHON_BORN_CHARGES}},		{{TAG \| PHON_BORN_CHARGES}},
	~~{{TAG \| PHON_G_CUTOFF}},~~
	{{TAG \| PHON_DOS}},		{{TAG \| PHON_DOS}},
	{{TAG \| PHON_SIGMA}},		{{TAG \| PHON_SIGMA}},

Miranda.henrique: Created page with "{{TAGDEF|PHON_G_CUTOFF| [3x3xNIONS real] }} {{DEF|PHON_G_CUTOFF|None|}} Description: {{TAG|PHON_G_CUTOFF}} sets the cutoff radius in reciprocal space used to determine the nu..."

2022-07-19T19:59:23Z

Created page with "{{TAGDEF|PHON_G_CUTOFF| [3x3xNIONS real] }} {{DEF|PHON_G_CUTOFF|None|}} Description: {{TAG|PHON_G_CUTOFF}} sets the cutoff radius in reciprocal space used to determine the nu..."

New page

{{TAGDEF|PHON_G_CUTOFF| [3x3xNIONS real] }}
{{DEF|PHON_G_CUTOFF|None|}}

Description: {{TAG|PHON_G_CUTOFF}} sets the cutoff radius in reciprocal space used to determine the number of G-vectors involved in the Ewald sum in polar phonon calculations.
----

If the material is polar (i.e. has more than one different atom type) a special treatment of the long-range dipole-dipole interaction is required to obtain a smooth phonon dispersion.
This is activated by setting {{TAG|LPHON_POLAR}}=.TRUE. and supplying the static dielectric tensor ({{TAG|PHON_DIELECTRIC}}) and the Born-effective charges ({{TAG|PHON_BORN_CHARGES}}) which can be obtained on a separate VASP run using the {{TAG|LEPSILON}} or {{TAG|LCALCEPS}} tag. The long-range part is evaluated using an Ewald sum with the number of G-vectors in reciprocal space being determined using a cutoff length ({{TAG|PHON_G_CUTOFF}}).
{{NB|mind| Only available as of VASP 6.3.2.}}

==Related tags and articles==
{{FILE| QPOINTS}},
{{TAG | LPHON_DISPERSION}},
{{TAG | PHON_NWRITE}},
{{TAG | LPHON_POLAR}},
{{TAG | PHON_DIELECTRIC}},
{{TAG | PHON_BORN_CHARGES}},
{{TAG | PHON_G_CUTOFF}},
{{TAG | PHON_DOS}},
{{TAG | PHON_SIGMA}},
{{TAG | PHON_NEDOS}}

{{sc|PHON_G_CUTOFF|Examples|Examples that use this tag}}

[[Category:INCAR tag]][[Category:Phonons]]