PSTRESS - Revision history

Csheldon at 12:10, 19 August 2024

2024-08-19T12:10:09Z

← Older revision		Revision as of 12:10, 19 August 2024
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	{{TAG\|PSTRESS}} can also be used to correct errors caused by the Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete plane wave basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of the Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at the desired cutoff and a very large energy cutoff (check the lines 'external pressure' in the {{TAG\|OUTCAR}} file and calculate		{{TAG\|PSTRESS}} can also be used to correct errors caused by the Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete plane wave basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of the Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at the desired cutoff and a very large energy cutoff (check the lines 'external pressure' in the {{TAG\|OUTCAR}} file and calculate
	pressure at cutoff you want to use <math> - </math> pressure at large cutoff; this must be a negative value). Before using this tag in this manner, please read the following section carefully: {{TAG \| ~~Energy vs volume~~ Volume ~~relaxations and Pulay stress~~}}.		pressure at cutoff you want to use <math> - </math> pressure at large cutoff; this must be a negative value). Before using this tag in this manner, please read the following section carefully: {{TAG \| Volume relaxation}}.

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

Mani: Add default value for PSTRESS

2024-01-31T16:09:25Z

Add default value for PSTRESS

← Older revision		Revision as of 16:09, 31 January 2024
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	{{TAGDEF\|PSTRESS\|[real]}}		{{TAGDEF\|PSTRESS\|[real]\|0}}

	Description: Sets the external pressure in kB or adds corrections to the stress tensor.		Description: Sets the external pressure in kB or adds corrections to the stress tensor.

Kresse at 06:48, 22 March 2023

2023-03-22T06:48:50Z

← Older revision		Revision as of 06:48, 22 March 2023
Line 1:		Line 1:
	{{TAGDEF\|PSTRESS\|[real]}}		{{TAGDEF\|PSTRESS\|[real]}}

	Description: Sets the external pressure in kB or ~~add~~ corrections to the stress tensor.		Description: Sets the external pressure in kB or adds corrections to the stress tensor.

	----		----
Line 15:		Line 15:

	{{TAG\|PSTRESS}} can also be used to correct errors caused by the Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete plane wave basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of the Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at the desired cutoff and a very large energy cutoff (check the lines 'external pressure' in the {{TAG\|OUTCAR}} file and calculate		{{TAG\|PSTRESS}} can also be used to correct errors caused by the Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete plane wave basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of the Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at the desired cutoff and a very large energy cutoff (check the lines 'external pressure' in the {{TAG\|OUTCAR}} file and calculate
	pressure at cutoff you want to use <math> - </math> pressure at ~~huge~~ cutoff; this must be a negative value). Before using this tag in this ~~way~~, please read the following section carefully {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.		pressure at cutoff you want to use <math> - </math> pressure at large cutoff; this must be a negative value). Before using this tag in this manner, please read the following section carefully: {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.

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

Kresse: Updated some mistakes in sign conventions. Improved wording. Explicitly discuss tensile and compressive stress and how this changes volume.

2023-03-21T18:39:37Z

Updated some mistakes in sign conventions. Improved wording. Explicitly discuss tensile and compressive stress and how this changes volume.

← Older revision		Revision as of 18:39, 21 March 2023
Line 1:		Line 1:
	{{TAGDEF\|PSTRESS\|[real]}}		{{TAGDEF\|PSTRESS\|[real]}}

	Description: ~~Set~~ the pressure in kB ~~and~~ add corrections to the stress tensor.		Description: Sets the external pressure in kB or add corrections to the stress tensor.

	----		----

	~~During [[Ionic minimization\|ionic minimization]], an energy term <math> E= V * \mathrm{PSTRESS} </math> is added to the total energy and the pressure set by~~ {{TAG\|PSTRESS}} is ~~added to the diagonals of the stress tensor. This allows performing structure optimization at a specific external pressure~~.		The unit of {{TAG\|PSTRESS}} is kB.

	In [[~~Molecular dynamics~~\|~~molecular-dynamics calculations~~]] ~~within the {{TAG\|NpT ensemble}}~~, {~~{TAG\|~~PSTRESS}~~} controls~~ the ~~target pressure for~~ the ~~Parinello-Rahman{{cite\|parrinello:prl:1980}}{{cite\|parrinello:jap:1981}} barostat. The unit~~ of {{TAG\|PSTRESS}} is kB.		During [[Ionic minimization\|ionic minimization]], an energy term <math> E= V \times \mathrm{PSTRESS} </math> is added to the total energy and the value of {{TAG\|PSTRESS}} is subtracted from the diagonals of the stress tensor. This allows to perform structure optimization at a specific external pressure.

	{{TAG\|PSTRESS}} can also be used to correct errors caused by Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at a very large cutoff ~~and the desired cutoff. Look for~~ the ~~line~~ 'external pressure' in the {{TAG\|OUTCAR}} file. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.		In [[Molecular dynamics\|molecular-dynamics calculations]] within the {{TAG\|NpT ensemble}}, {{TAG\|PSTRESS}} controls the target pressure for the Parinello-Rahman{{cite\|parrinello:prl:1980}}{{cite\|parrinello:jap:1981}} barostat.

			Generally, if a negative value is supplied, the system is under effective tensile strain and during relaxations (or molecular dynamics simulations) the volume
			will increase. If a positive value is supplied, the system is under compressive strain; this will decrease the volume during relaxations and molecular dynamics simulations.

			{{TAG\|PSTRESS}} can also be used to correct errors caused by the Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete plane wave basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of the Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at the desired cutoff and a very large energy cutoff (check the lines 'external pressure' in the {{TAG\|OUTCAR}} file and calculate
			pressure at cutoff you want to use <math> - </math> pressure at huge cutoff; this must be a negative value). Before using this tag in this way, please read the following section carefully {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.

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

Huebsch at 10:00, 5 July 2022

2022-07-05T10:00:29Z

← Older revision		Revision as of 10:00, 5 July 2022
Line 7:		Line 7:
	During [[Ionic minimization\|ionic minimization]], an energy term <math> E= V * \mathrm{PSTRESS} </math> is added to the total energy and the pressure set by {{TAG\|PSTRESS}} is added to the diagonals of the stress tensor. This allows performing structure optimization at a specific external pressure.		During [[Ionic minimization\|ionic minimization]], an energy term <math> E= V * \mathrm{PSTRESS} </math> is added to the total energy and the pressure set by {{TAG\|PSTRESS}} is added to the diagonals of the stress tensor. This allows performing structure optimization at a specific external pressure.

	In [[Molecular dynamics\|molecular-dynamics calculations]] within the {{TAG\|NpT ensemble}}, {{TAG\|PSTRESS}} controls the target pressure for the Parinello-Rahman{{cite\|parrinello:prl:1980}}{{cite\|parrinello:jap:1981}} barostat. The unit of {{TAG\|PSTRESS}} is in kB.		In [[Molecular dynamics\|molecular-dynamics calculations]] within the {{TAG\|NpT ensemble}}, {{TAG\|PSTRESS}} controls the target pressure for the Parinello-Rahman{{cite\|parrinello:prl:1980}}{{cite\|parrinello:jap:1981}} barostat. The unit of {{TAG\|PSTRESS}} is kB.

	{{TAG\|PSTRESS}} can also be used to correct errors caused by Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at a very large cutoff and the desired cutoff. Look for the line 'external pressure' in the {{TAG\|OUTCAR}} file. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.		{{TAG\|PSTRESS}} can also be used to correct errors caused by Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at a very large cutoff and the desired cutoff. Look for the line 'external pressure' in the {{TAG\|OUTCAR}} file. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.

Huebsch at 09:38, 5 July 2022

2022-07-05T09:38:51Z

← Older revision		Revision as of 09:38, 5 July 2022
Line 1:		Line 1:
	{{TAGDEF\|PSTRESS\|[real]}}		{{TAGDEF\|PSTRESS\|[real]}}

	Description: ~~This tag controls whether Pulay~~ corrections ~~are added~~ to the stress tensor ~~or not. In molecular-dynamics calculations and structure optimization, it controls the pressure~~.		Description: Set the pressure in kB and add corrections to the stress tensor.

	----		----
	If {{TAG\|PSTRESS}} is specified VASP will add this pressure to the diagonals of the stress tensor and add an energy term <math> E= V * \mathrm{PSTRESS} </math> to the energy. This allows the user to converge to a specified external pressure.

	{~~{TAG\|~~PSTRESS}~~} can be also used~~ to ~~correct for errors caused by~~ the ~~Pulay stress, that is, errors in~~ the ~~calculated stress tensor caused~~ by ~~basis set incompleteness errors. In order to correct for the Pulay stress error, set~~ {{TAG\|PSTRESS}} to the ~~negative value, that you obtain by calculating~~ the ~~pressure~~ at a ~~very large cutoff and the desired cutoff. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}~~.		During [[Ionic minimization\|ionic minimization]], an energy term <math> E= V * \mathrm{PSTRESS} </math> is added to the total energy and the pressure set by {{TAG\|PSTRESS}} is added to the diagonals of the stress tensor. This allows performing structure optimization at a specific external pressure.

	In molecular-dynamics calculations within the {{TAG\|NpT ensemble}} ~~this tag~~ controls the target pressure. The unit of {{TAG\|PSTRESS}} is in kB.		In [[Molecular dynamics\|molecular-dynamics calculations]] within the {{TAG\|NpT ensemble}}, {{TAG\|PSTRESS}} controls the target pressure for the Parinello-Rahman{{cite\|parrinello:prl:1980}}{{cite\|parrinello:jap:1981}} barostat. The unit of {{TAG\|PSTRESS}} is in kB.

			{{TAG\|PSTRESS}} can also be used to correct errors caused by Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at a very large cutoff and the desired cutoff. Look for the line 'external pressure' in the {{TAG\|OUTCAR}} file. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.

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

Huebsch at 13:08, 4 July 2022

2022-07-04T13:08:49Z

← Older revision		Revision as of 13:08, 4 July 2022
Line 1:		Line 1:
	{{TAGDEF\|PSTRESS\|[real]}}		{{TAGDEF\|PSTRESS\|[real]}}

	Description: This tag controls whether Pulay corrections are added to the stress tensor or not. In molecular-dynamics calculations, it controls the pressure.		Description: This tag controls whether Pulay corrections are added to the stress tensor or not. In molecular-dynamics calculations and structure optimization, it controls the pressure.

	----		----

Karsai at 12:48, 8 April 2022

2022-04-08T12:48:45Z

← Older revision		Revision as of 12:48, 8 April 2022
Line 4:		Line 4:

	----		----
	If ~~the~~ {{TAG\|PSTRESS}} ~~tag~~ is specified VASP will add this pressure to the diagonals of the stress tensor and add an energy term <math> E= V * \mathrm{PSTRESS} </math> to the energy. This allows the user to converge to a specified external pressure.		If {{TAG\|PSTRESS}} is specified VASP will add this pressure to the diagonals of the stress tensor and add an energy term <math> E= V * \mathrm{PSTRESS} </math> to the energy. This allows the user to converge to a specified external pressure.

	{{TAG\|PSTRESS}} can be also used to correct for errors caused by the Pulay stress, that is, errors in the calculated stress tensor caused by basis set incompleteness errors. In order to correct for the Pulay stress error, set {{TAG\|PSTRESS}} to the negative value, that you obtain by calculating the pressure at a very large cutoff and the desired cutoff. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.		{{TAG\|PSTRESS}} can be also used to correct for errors caused by the Pulay stress, that is, errors in the calculated stress tensor caused by basis set incompleteness errors. In order to correct for the Pulay stress error, set {{TAG\|PSTRESS}} to the negative value, that you obtain by calculating the pressure at a very large cutoff and the desired cutoff. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.

Karsai at 12:48, 8 April 2022

2022-04-08T12:48:30Z

← Older revision		Revision as of 12:48, 8 April 2022
Line 1:		Line 1:
	{{TAGDEF\|PSTRESS\|[real]}}		{{TAGDEF\|PSTRESS\|[real]}}

	Description: This ~~flag~~ controls whether Pulay corrections are added to the stress tensor or not. In molecular-dynamics calculations, it controls the pressure.		Description: This tag controls whether Pulay corrections are added to the stress tensor or not. In molecular-dynamics calculations, it controls the pressure.

	----		----
	If the {{TAG\|PSTRESS}} tag is specified VASP will add this pressure to the diagonals of the stress tensor and add an energy term <math> E= V * \mathrm{PSTRESS} </math> to the energy. This allows the user to converge to a specified external pressure.		If the {{TAG\|PSTRESS}} tag is specified VASP will add this pressure to the diagonals of the stress tensor and add an energy term <math> E= V * \mathrm{PSTRESS} </math> to the energy. This allows the user to converge to a specified external pressure.

	{{TAG\|PSTRESS}} can be also used to correct for errors caused by the Pulay stress, that is, errors in the calculated stress tensor caused by basis set incompleteness errors. In order to correct for the Pulay stress error, set {{TAG\|PSTRESS}} to the negative value, that you obtain by calculating the pressure at a very large cutoff and the desired cutoff. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}		{{TAG\|PSTRESS}} can be also used to correct for errors caused by the Pulay stress, that is, errors in the calculated stress tensor caused by basis set incompleteness errors. In order to correct for the Pulay stress error, set {{TAG\|PSTRESS}} to the negative value, that you obtain by calculating the pressure at a very large cutoff and the desired cutoff. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.

	In molecular-dynamics calculations within the {{TAG\|NpT ensemble}} this tag controls the target pressure. The unit of {{TAG\|PSTRESS}} is in kB.		In molecular-dynamics calculations within the {{TAG\|NpT ensemble}} this tag controls the target pressure. The unit of {{TAG\|PSTRESS}} is in kB.

Huebsch at 08:34, 7 April 2022

2022-04-07T08:34:35Z

← Older revision		Revision as of 08:34, 7 April 2022
Line 1:		Line 1:
	{{TAGDEF\|PSTRESS\|[real]}}		{{TAGDEF\|PSTRESS\|[real]}}

	Description: This flag controls whether Pulay corrections are added to the stress tensor or not. In molecular dynamics calculations it controls the pressure.		Description: This flag controls whether Pulay corrections are added to the stress tensor or not. In molecular-dynamics calculations, it controls the pressure.

	----		----
	If the {{TAG\|PSTRESS}} tag is specified VASP will add this pressure to the diagonals of the stress tensor and add an energy term <math> E= V * \mathrm{PSTRESS} </math> to the energy. This allows the user to converge to a specified external pressure.		If the {{TAG\|PSTRESS}} tag is specified VASP will add this pressure to the diagonals of the stress tensor and add an energy term <math> E= V * \mathrm{PSTRESS} </math> to the energy. This allows the user to converge to a specified external pressure.

	{{TAG\|PSTRESS}} can be also used to correct for errors ~~cause~~ by the Pulay stress, that is, errors in the calculated stress tensor ~~causes~~ by basis set incompleteness errors. In order to correct for the Pulay stress error, set {{TAG\|PSTRESS}} to the negative value, that you obtain by calculating the pressure at a very large cutoff and the desired cutoff. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}		{{TAG\|PSTRESS}} can be also used to correct for errors caused by the Pulay stress, that is, errors in the calculated stress tensor caused by basis set incompleteness errors. In order to correct for the Pulay stress error, set {{TAG\|PSTRESS}} to the negative value, that you obtain by calculating the pressure at a very large cutoff and the desired cutoff. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}

	In molecular dynamics calculations within the {{TAG\|NpT ensemble}} this tag controls the target pressure. The unit of {{TAG\|PSTRESS}} is in kB.		In molecular-dynamics calculations within the {{TAG\|NpT ensemble}} this tag controls the target pressure. The unit of {{TAG\|PSTRESS}} is in kB.

	{{sc\|PSTRESS\|Examples\|Examples that use this tag}}		{{sc\|PSTRESS\|Examples\|Examples that use this tag}}
	----		----

	[[Category:INCAR]][[Category: Molecular ~~Dynamics~~]][[Category:Ensembles]][[Category:~~Structural Optimization~~]][[Category:Forces]]		[[Category:INCAR tag]][[Category: Molecular dynamics]][[Category:Ensembles]][[Category:Ionic minimization]][[Category:Forces]]

← Older revision		Revision as of 12:10, 19 August 2024
Line 15:		Line 15:

	{{TAG\|PSTRESS}} can also be used to correct errors caused by the Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete plane wave basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of the Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at the desired cutoff and a very large energy cutoff (check the lines 'external pressure' in the {{TAG\|OUTCAR}} file and calculate		{{TAG\|PSTRESS}} can also be used to correct errors caused by the Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete plane wave basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of the Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at the desired cutoff and a very large energy cutoff (check the lines 'external pressure' in the {{TAG\|OUTCAR}} file and calculate
	pressure at cutoff you want to use <math> - </math> pressure at large cutoff; this must be a negative value). Before using this tag in this manner, please read the following section carefully: {{TAG \| ~~Energy vs volume~~ Volume ~~relaxations and Pulay stress~~}}.		pressure at cutoff you want to use <math> - </math> pressure at large cutoff; this must be a negative value). Before using this tag in this manner, please read the following section carefully: {{TAG \| Volume relaxation}}.

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

← Older revision		Revision as of 18:39, 21 March 2023
Line 1:		Line 1:
	{{TAGDEF\|PSTRESS\|[real]}}		{{TAGDEF\|PSTRESS\|[real]}}

	Description: ~~Set~~ the pressure in kB ~~and~~ add corrections to the stress tensor.		Description: Sets the external pressure in kB or add corrections to the stress tensor.

	----		----

	~~During [[Ionic minimization\|ionic minimization]], an energy term <math> E= V * \mathrm{PSTRESS} </math> is added to the total energy and the pressure set by~~ {{TAG\|PSTRESS}} is ~~added to the diagonals of the stress tensor. This allows performing structure optimization at a specific external pressure~~.		The unit of {{TAG\|PSTRESS}} is kB.

	In [[~~Molecular dynamics~~\|~~molecular-dynamics calculations~~]] ~~within the {{TAG\|NpT ensemble}}~~, {~~{TAG\|~~PSTRESS}~~} controls~~ the ~~target pressure for~~ the ~~Parinello-Rahman{{cite\|parrinello:prl:1980}}{{cite\|parrinello:jap:1981}} barostat. The unit~~ of {{TAG\|PSTRESS}} is kB.		During [[Ionic minimization\|ionic minimization]], an energy term <math> E= V \times \mathrm{PSTRESS} </math> is added to the total energy and the value of {{TAG\|PSTRESS}} is subtracted from the diagonals of the stress tensor. This allows to perform structure optimization at a specific external pressure.

	{{TAG\|PSTRESS}} can also be used to correct errors caused by Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at a very large cutoff ~~and the desired cutoff. Look for~~ the ~~line~~ 'external pressure' in the {{TAG\|OUTCAR}} file. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.		In [[Molecular dynamics\|molecular-dynamics calculations]] within the {{TAG\|NpT ensemble}}, {{TAG\|PSTRESS}} controls the target pressure for the Parinello-Rahman{{cite\|parrinello:prl:1980}}{{cite\|parrinello:jap:1981}} barostat.

			Generally, if a negative value is supplied, the system is under effective tensile strain and during relaxations (or molecular dynamics simulations) the volume
			will increase. If a positive value is supplied, the system is under compressive strain; this will decrease the volume during relaxations and molecular dynamics simulations.

			{{TAG\|PSTRESS}} can also be used to correct errors caused by the Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete plane wave basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of the Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at the desired cutoff and a very large energy cutoff (check the lines 'external pressure' in the {{TAG\|OUTCAR}} file and calculate
			pressure at cutoff you want to use <math> - </math> pressure at huge cutoff; this must be a negative value). Before using this tag in this way, please read the following section carefully {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.

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

← Older revision		Revision as of 10:00, 5 July 2022
Line 7:		Line 7:
	During [[Ionic minimization\|ionic minimization]], an energy term <math> E= V * \mathrm{PSTRESS} </math> is added to the total energy and the pressure set by {{TAG\|PSTRESS}} is added to the diagonals of the stress tensor. This allows performing structure optimization at a specific external pressure.		During [[Ionic minimization\|ionic minimization]], an energy term <math> E= V * \mathrm{PSTRESS} </math> is added to the total energy and the pressure set by {{TAG\|PSTRESS}} is added to the diagonals of the stress tensor. This allows performing structure optimization at a specific external pressure.

	In [[Molecular dynamics\|molecular-dynamics calculations]] within the {{TAG\|NpT ensemble}}, {{TAG\|PSTRESS}} controls the target pressure for the Parinello-Rahman{{cite\|parrinello:prl:1980}}{{cite\|parrinello:jap:1981}} barostat. The unit of {{TAG\|PSTRESS}} is in kB.		In [[Molecular dynamics\|molecular-dynamics calculations]] within the {{TAG\|NpT ensemble}}, {{TAG\|PSTRESS}} controls the target pressure for the Parinello-Rahman{{cite\|parrinello:prl:1980}}{{cite\|parrinello:jap:1981}} barostat. The unit of {{TAG\|PSTRESS}} is kB.

	{{TAG\|PSTRESS}} can also be used to correct errors caused by Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at a very large cutoff and the desired cutoff. Look for the line 'external pressure' in the {{TAG\|OUTCAR}} file. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.		{{TAG\|PSTRESS}} can also be used to correct errors caused by Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at a very large cutoff and the desired cutoff. Look for the line 'external pressure' in the {{TAG\|OUTCAR}} file. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.

← Older revision		Revision as of 09:38, 5 July 2022
Line 1:		Line 1:
	{{TAGDEF\|PSTRESS\|[real]}}		{{TAGDEF\|PSTRESS\|[real]}}

	Description: ~~This tag controls whether Pulay~~ corrections ~~are added~~ to the stress tensor ~~or not. In molecular-dynamics calculations and structure optimization, it controls the pressure~~.		Description: Set the pressure in kB and add corrections to the stress tensor.

	----		----
	If {{TAG\|PSTRESS}} is specified VASP will add this pressure to the diagonals of the stress tensor and add an energy term <math> E= V * \mathrm{PSTRESS} </math> to the energy. This allows the user to converge to a specified external pressure.

	{~~{TAG\|~~PSTRESS}~~} can be also used~~ to ~~correct for errors caused by~~ the ~~Pulay stress, that is, errors in~~ the ~~calculated stress tensor caused~~ by ~~basis set incompleteness errors. In order to correct for the Pulay stress error, set~~ {{TAG\|PSTRESS}} to the ~~negative value, that you obtain by calculating~~ the ~~pressure~~ at a ~~very large cutoff and the desired cutoff. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}~~.		During [[Ionic minimization\|ionic minimization]], an energy term <math> E= V * \mathrm{PSTRESS} </math> is added to the total energy and the pressure set by {{TAG\|PSTRESS}} is added to the diagonals of the stress tensor. This allows performing structure optimization at a specific external pressure.

	In molecular-dynamics calculations within the {{TAG\|NpT ensemble}} ~~this tag~~ controls the target pressure. The unit of {{TAG\|PSTRESS}} is in kB.		In [[Molecular dynamics\|molecular-dynamics calculations]] within the {{TAG\|NpT ensemble}}, {{TAG\|PSTRESS}} controls the target pressure for the Parinello-Rahman{{cite\|parrinello:prl:1980}}{{cite\|parrinello:jap:1981}} barostat. The unit of {{TAG\|PSTRESS}} is in kB.

			{{TAG\|PSTRESS}} can also be used to correct errors caused by Pulay stress, i.e., errors in the calculated stress tensor caused by the incomplete basis set. To correct for Pulay-stress errors, set {{TAG\|PSTRESS}} to the negative value of Pulay stress. The Pulay stress is computed by taking the difference between the external pressure at a very large cutoff and the desired cutoff. Look for the line 'external pressure' in the {{TAG\|OUTCAR}} file. Before using this tag in this way, please read the section {{TAG \| Energy vs volume Volume relaxations and Pulay stress}}.

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