POTIM - Revision history

Schlipf: /* Related tags and articles */

2024-10-18T11:50:56Z

Huebsch at 08:28, 7 April 2022

2022-04-07T08:28:50Z

← Older revision		Revision as of 08:28, 7 April 2022
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	----		----

	[[Category:INCAR]][[Category:~~Structural Optimization~~]][[Category:Molecular ~~Dynamics]][[Category:Ionic Minimization Methods]][[Category:Lattice Vibrations~~]][[Category:Phonons]]		[[Category:INCAR tag]][[Category:Ionic minimization]][[Category:Molecular dynamics]][[Category:Phonons]]

Huebsch at 08:17, 29 March 2022

2022-03-29T08:17:42Z

← Older revision		Revision as of 08:17, 29 March 2022
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	* For {{TAG\|IBRION}} = 0, {{TAG\|POTIM}} gives the time step (in fs) in all ab-initio Molecular Dynamics runs, it ''has'' to be supplied therefore, otherwise VASP crashes immediately after having started.		* For {{TAG\|IBRION}} = 0, {{TAG\|POTIM}} gives the time step (in fs) in all ab-initio Molecular Dynamics runs, it ''has'' to be supplied therefore, otherwise VASP crashes immediately after having started.

	* For {{TAG\|IBRION}} =1, 2, and 3, which corresponds to ionic relaxation using a quasi-Newton algorithm, conjugate-gradient algorithm, and damped molecular dynamics, respectively, the {{TAG\|POTIM}} tag serves as a scaling constant for the step widths. ~~Especially the~~ quasi-Newton algorithm is sensitive to the choice of this parameter.		* For {{TAG\|IBRION}} =1, 2, and 3, which corresponds to ionic relaxation using a quasi-Newton algorithm, conjugate-gradient algorithm, and damped molecular dynamics, respectively, the {{TAG\|POTIM}} tag serves as a scaling constant for the step widths. The quasi-Newton algorithm is especially sensitive to the choice of this parameter.

	* For {{TAG\|IBRION}} = 5, and 6, a phonon calculations using the finite differences approach is done, where {{TAG\|POTIM}} is the width of the displacement of each ion to calculate the Hessian Matrix.		* For {{TAG\|IBRION}} = 5, and 6, a phonon calculations using the finite differences approach is done, where {{TAG\|POTIM}} is the width of the displacement of each ion to calculate the Hessian Matrix.
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	{{NB\|mind\| For VASP.5.1 and newer releases, {{TAG\|POTIM}} is automatically reset to 0.015 Å, if the supplied value for {{TAG\|POTIM}} is unreasonably large.\|:}}		{{NB\|mind\| For VASP.5.1 and newer releases, {{TAG\|POTIM}} is automatically reset to 0.015 Å, if the supplied value for {{TAG\|POTIM}} is unreasonably large.\|:}}
	</span>		</span>
	== Related ~~Tags~~ and ~~Sections~~ ==		== Related tags and articles ==
	{{TAG\|IBRION}}, {{TAG\|NFREE}}		{{TAG\|IBRION}}, {{TAG\|NFREE}}

Huebsch at 12:46, 21 October 2021

2021-10-21T12:46:53Z

← Older revision		Revision as of 12:46, 21 October 2021
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	{{TAGDEF\|POTIM\|[real]}}		{{TAGDEF\|POTIM\|[real]}}

	{{DEF\|POTIM\|none,\| ''must'' be set if {{TAG\|IBRION}}{{=}} 0 (MD)\|0.5\| if {{TAG\|IBRION}}{{=}} 1,2,3 (ionic relaxation) and 5 (up to VASP.4.6)\|0.015\|~~for~~ {{TAG\|IBRION}}{{=}}5 (~~up from~~ VASP.5.1)}}		{{DEF\|POTIM\|none,\| ''must'' be set if {{TAG\|IBRION}}{{=}} 0 (MD)\|0.5\| if {{TAG\|IBRION}}{{=}} 1, 2, and 3 (ionic relaxation), and 5 (up to VASP.4.6)\|0.015\|if {{TAG\|IBRION}}{{=}}5, and 6 (as of VASP.5.1)}}

	Description: {{TAG\|POTIM}} sets the time step ~~(MD)~~ or step width ~~scaling (~~ionic relaxations).		Description: {{TAG\|POTIM}} sets the time step in molecular dynamics or the step width in ionic relaxations.

	----		----
	~~<span>~~
	{{TAG\|IBRION}} = 0:		* For {{TAG\|IBRION}} = 0, {{TAG\|POTIM}} gives the time step (in fs) in all ab-initio Molecular Dynamics runs, it ''has'' to be supplied therefore, otherwise VASP crashes immediately after having started.
	:{{TAG\|POTIM}} gives the time step (in fs) in all ab-initio Molecular Dynamics runs, it ''has'' to be supplied therefore, otherwise VASP crashes immediately after having started.
	~~</span>~~		* For {{TAG\|IBRION}} =1, 2, and 3, which corresponds to ionic relaxation using a quasi-Newton algorithm, conjugate-gradient algorithm, and damped molecular dynamics, respectively, the {{TAG\|POTIM}} tag serves as a scaling constant for the step widths. Especially the quasi-Newton algorithm is sensitive to the choice of this parameter.
	~~<span>~~
	{{TAG\|IBRION}} =1,2,3:		* For {{TAG\|IBRION}} = 5, and 6, a phonon calculations using the finite differences approach is done, where {{TAG\|POTIM}} is the width of the displacement of each ion to calculate the Hessian Matrix.
	~~:In all minimization algorithms (~~quasi-Newton, conjugate gradient, and damped molecular dynamics) {{TAG\|POTIM}} serves as a scaling constant for the step widths. Especially the ~~Quasi~~-Newton algorithm is sensitive to the choice of this parameter.		:VASP.4.6 and older releases: {{TAG\|POTIM}} has to be small enough to ensure that the displacements are within the harmonic limit. The vibrational frequencies using the frozen phonon approach are based on the harmonic approximation.
	~~</span>~~		{{NB\|mind\| For VASP.5.1 and newer releases, {{TAG\|POTIM}} is automatically reset to 0.015 Å, if the supplied value for {{TAG\|POTIM}} is unreasonably large.\|:}}
	~~<span>~~
	{{TAG\|IBRION}} = 5,6:
	~~:In frozen~~ phonon calculations, {{TAG\|POTIM}} ~~gives~~ the width of the displacement of each ion to calculate the Hessian Matrix.
	:~~'''~~VASP.4.6~~'''~~ and older releases: {{TAG\|POTIM}} has to be small enough to ensure that the displacements are within the harmonic limit. The vibrational frequencies using the frozen phonon approach are based on the harmonic approximation.
	~~:'''~~VASP.5.1~~'''~~ and newer releases~~: if the supplied value for {{TAG\|POTIM}} is unreasonably large~~, {{TAG\|POTIM}} is automatically reset to 0.015 Å.
	</span>		</span>
	== Related Tags and Sections ==		== Related Tags and Sections ==

Karsai at 09:35, 8 August 2019

2019-08-08T09:35:47Z

← Older revision		Revision as of 09:35, 8 August 2019
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	<span>		<span>
	{{TAG\|IBRION}} =1,2,3:		{{TAG\|IBRION}} =1,2,3:
	:In all minimization algorithms (quasi-Newton, conjugate gradient, and damped molecular dynamics) {{TAG\|POTIM}} serves as a scaling constant for the step widths. Especially the Quasi-Newton algorithm is sensitive to the choice of this parameter		:In all minimization algorithms (quasi-Newton, conjugate gradient, and damped molecular dynamics) {{TAG\|POTIM}} serves as a scaling constant for the step widths. Especially the Quasi-Newton algorithm is sensitive to the choice of this parameter.
	</span>		</span>
	<span>		<span>

Karsai at 10:41, 19 April 2019

2019-04-19T10:41:35Z

← Older revision		Revision as of 10:41, 19 April 2019
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	{{sc\|POTIM\|Examples\|Examples that use this tag}}		{{sc\|POTIM\|Examples\|Examples that use this tag}}
	----		----
	~~[[The_VASP_Manual\|Contents]]~~

	[[Category:INCAR]][[Category:Structural Optimization]][[Category:Molecular Dynamics]][[Category:Ionic Minimization Methods]][[Category:Lattice Vibrations]][[Category:Phonons]]		[[Category:INCAR]][[Category:Structural Optimization]][[Category:Molecular Dynamics]][[Category:Ionic Minimization Methods]][[Category:Lattice Vibrations]][[Category:Phonons]]

Karsai at 07:45, 9 April 2019

2019-04-09T07:45:51Z

← Older revision		Revision as of 07:45, 9 April 2019
Line 27:		Line 27:
	[[The_VASP_Manual\|Contents]]		[[The_VASP_Manual\|Contents]]

	[[Category:INCAR]][[Category:Structural Optimization]][[Category:Molecular Dynamics]][[Category:Ionic Minimization Methods]]		[[Category:INCAR]][[Category:Structural Optimization]][[Category:Molecular Dynamics]][[Category:Ionic Minimization Methods]][[Category:Lattice Vibrations]][[Category:Phonons]]

Karsai at 18:38, 7 March 2019

2019-03-07T18:38:59Z

← Older revision		Revision as of 18:38, 7 March 2019
Line 27:		Line 27:
	[[The_VASP_Manual\|Contents]]		[[The_VASP_Manual\|Contents]]

	[[Category:INCAR]][[Category:Molecular Dynamics]][[Category:Ionic Minimization Methods]]		[[Category:INCAR]][[Category:Structural Optimization]][[Category:Molecular Dynamics]][[Category:Ionic Minimization Methods]]

Karsai at 14:34, 22 February 2019

2019-02-22T14:34:06Z

← Older revision		Revision as of 14:34, 22 February 2019
Line 27:		Line 27:
	[[The_VASP_Manual\|Contents]]		[[The_VASP_Manual\|Contents]]

	[[Category:INCAR]][[Category:Molecular Dynamics]]		[[Category:INCAR]][[Category:Molecular Dynamics]][[Category:Ionic Minimization Methods]]

Karsai at 17:20, 15 February 2019

2019-02-15T17:20:32Z

← Older revision		Revision as of 17:20, 15 February 2019
Line 27:		Line 27:
	[[The_VASP_Manual\|Contents]]		[[The_VASP_Manual\|Contents]]

	[[Category:INCAR]][[Category:Dynamics]]		[[Category:INCAR]][[Category:Molecular Dynamics]]

← Older revision		Revision as of 11:50, 18 October 2024
Line 16:		Line 16:
	</span>		</span>
	== Related tags and articles ==		== Related tags and articles ==
	{{TAG\|IBRION}}, {{TAG\|NFREE}}		[[structure optimization]], {{TAG\|IBRION}}, {{TAG\|NFREE}}

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

← Older revision		Revision as of 12:46, 21 October 2021
Line 1:		Line 1:
	{{TAGDEF\|POTIM\|[real]}}		{{TAGDEF\|POTIM\|[real]}}

	{{DEF\|POTIM\|none,\| ''must'' be set if {{TAG\|IBRION}}{{=}} 0 (MD)\|0.5\| if {{TAG\|IBRION}}{{=}} 1,2,3 (ionic relaxation) and 5 (up to VASP.4.6)\|0.015\|~~for~~ {{TAG\|IBRION}}{{=}}5 (~~up from~~ VASP.5.1)}}		{{DEF\|POTIM\|none,\| ''must'' be set if {{TAG\|IBRION}}{{=}} 0 (MD)\|0.5\| if {{TAG\|IBRION}}{{=}} 1, 2, and 3 (ionic relaxation), and 5 (up to VASP.4.6)\|0.015\|if {{TAG\|IBRION}}{{=}}5, and 6 (as of VASP.5.1)}}

	Description: {{TAG\|POTIM}} sets the time step ~~(MD)~~ or step width ~~scaling (~~ionic relaxations).		Description: {{TAG\|POTIM}} sets the time step in molecular dynamics or the step width in ionic relaxations.

	----		----
	~~<span>~~
	{{TAG\|IBRION}} = 0:		* For {{TAG\|IBRION}} = 0, {{TAG\|POTIM}} gives the time step (in fs) in all ab-initio Molecular Dynamics runs, it ''has'' to be supplied therefore, otherwise VASP crashes immediately after having started.
	:{{TAG\|POTIM}} gives the time step (in fs) in all ab-initio Molecular Dynamics runs, it ''has'' to be supplied therefore, otherwise VASP crashes immediately after having started.
	~~</span>~~		* For {{TAG\|IBRION}} =1, 2, and 3, which corresponds to ionic relaxation using a quasi-Newton algorithm, conjugate-gradient algorithm, and damped molecular dynamics, respectively, the {{TAG\|POTIM}} tag serves as a scaling constant for the step widths. Especially the quasi-Newton algorithm is sensitive to the choice of this parameter.
	~~<span>~~
	{{TAG\|IBRION}} =1,2,3:		* For {{TAG\|IBRION}} = 5, and 6, a phonon calculations using the finite differences approach is done, where {{TAG\|POTIM}} is the width of the displacement of each ion to calculate the Hessian Matrix.
	~~:In all minimization algorithms (~~quasi-Newton, conjugate gradient, and damped molecular dynamics) {{TAG\|POTIM}} serves as a scaling constant for the step widths. Especially the ~~Quasi~~-Newton algorithm is sensitive to the choice of this parameter.		:VASP.4.6 and older releases: {{TAG\|POTIM}} has to be small enough to ensure that the displacements are within the harmonic limit. The vibrational frequencies using the frozen phonon approach are based on the harmonic approximation.
	~~</span>~~		{{NB\|mind\| For VASP.5.1 and newer releases, {{TAG\|POTIM}} is automatically reset to 0.015 Å, if the supplied value for {{TAG\|POTIM}} is unreasonably large.\|:}}
	~~<span>~~
	{{TAG\|IBRION}} = 5,6:
	~~:In frozen~~ phonon calculations, {{TAG\|POTIM}} ~~gives~~ the width of the displacement of each ion to calculate the Hessian Matrix.
	:~~'''~~VASP.4.6~~'''~~ and older releases: {{TAG\|POTIM}} has to be small enough to ensure that the displacements are within the harmonic limit. The vibrational frequencies using the frozen phonon approach are based on the harmonic approximation.
	~~:'''~~VASP.5.1~~'''~~ and newer releases~~: if the supplied value for {{TAG\|POTIM}} is unreasonably large~~, {{TAG\|POTIM}} is automatically reset to 0.015 Å.
	</span>		</span>
	== Related Tags and Sections ==		== Related Tags and Sections ==