ISIF - Revision history

Csheldon at 11:41, 9 February 2026

2026-02-09T11:41:24Z

← Older revision		Revision as of 11:41, 9 February 2026
Line 1:		Line 1:
	{{TAGDEF\|ISIF\|0 {{!}} 1 {{!}} 2 {{!}} 3 {{!}} 4 {{!}} 5 {{!}} 6 {{!}} 7 {{!}} 8}}		{{TAGDEF\|ISIF\|0 {{!}} 1 {{!}} 2 {{!}} 3 {{!}} 4 {{!}} 5 {{!}} 6 {{!}} 7 {{!}} 8}}
	{{DEF\|ISIF\|0\|for {{TAG\|IBRION\|0}} (molecular dynamics) or {{TAG\|LHFCALC\|.TRUE.}}\|2\|else} ~~(hybrid functionals)~~}		{{DEF\|ISIF\|0\|for {{TAG\|IBRION\|0}} (molecular dynamics) or {{TAG\|LHFCALC\|.TRUE.}} (hybrid functionals)\|2\|else}}

	Description: Determines if the stress tensor is calculated and which ionic degrees of freedom are varied.		Description: Determines if the stress tensor is calculated and which ionic degrees of freedom are varied.
	----		----

Csheldon at 11:40, 9 February 2026

2026-02-09T11:40:47Z

← Older revision		Revision as of 11:40, 9 February 2026
Line 1:		Line 1:
	{{TAGDEF\|ISIF\|0 {{!}} 1 {{!}} 2 {{!}} 3 {{!}} 4 {{!}} 5 {{!}} 6 {{!}} 7 {{!}} 8}}		{{TAGDEF\|ISIF\|0 {{!}} 1 {{!}} 2 {{!}} 3 {{!}} 4 {{!}} 5 {{!}} 6 {{!}} 7 {{!}} 8}}
	{{DEF\|ISIF\|0\|for {{TAG\|IBRION\|0}} (molecular dynamics) or {{TAG\|LHFCALC\|.TRUE.}}\|2\|else}}		{{DEF\|ISIF\|0\|for {{TAG\|IBRION\|0}} (molecular dynamics) or {{TAG\|LHFCALC\|.TRUE.}}\|2\|else} (hybrid functionals)}

	Description: Determines if the stress tensor is calculated and which ionic degrees of freedom are varied.		Description: Determines if the stress tensor is calculated and which ionic degrees of freedom are varied.

Csheldon at 11:40, 9 February 2026

2026-02-09T11:40:14Z

← Older revision		Revision as of 11:40, 9 February 2026
Line 49:		Line 49:
	{{NB\|warning\|The PAW basis for the [[:Category:Electronic minimization\|electronic minimization]] is not adjusted when the structure is varied during a calculation.\|:}}		{{NB\|warning\|The PAW basis for the [[:Category:Electronic minimization\|electronic minimization]] is not adjusted when the structure is varied during a calculation.\|:}}
	:Therefore, carefully consider effects such as [[Pulay_stress\|Pulay stress]] and choose generous settings for the [[:Category:Electronic minimization\|electronic minimization]]. Generally, volume changes should be done only with an increased energy cutoff, e.g., {{TAG\|ENCUT\|1.3×max({{TAG\|ENMAX}})}}, and {{TAG\|PREC\|High}}.		:Therefore, carefully consider effects such as [[Pulay_stress\|Pulay stress]] and choose generous settings for the [[:Category:Electronic minimization\|electronic minimization]]. Generally, volume changes should be done only with an increased energy cutoff, e.g., {{TAG\|ENCUT\|1.3×max({{TAG\|ENMAX}})}}, and {{TAG\|PREC\|High}}.
	* To further control the ionic degrees of freedom that can vary during the calculation, set `Selective dynamics` in the {{FILE\|POSCAR}} file.		* To further control the ionic degrees of freedom that can vary during the calculation, set <code>Selective dynamics</code> in the {{FILE\|POSCAR}} file.
	* {{TAG\|ISIF\|8}} is only available as of VASP.6.4.1.		* {{TAG\|ISIF\|8}} is only available as of VASP.6.4.1.
	== Related tags and articles ==		== Related tags and articles ==

Csheldon at 11:39, 9 February 2026

2026-02-09T11:39:58Z

← Older revision		Revision as of 11:39, 9 February 2026
Line 12:		Line 12:
	This might be different from other first principles codes.		This might be different from other first principles codes.
	A positive in the diagonals means that the system is under compressive strain and wants to expand. A negative value implies that the system is under tensile strain and wants to reduce its volume. The stress tensor is symmetric <math>\sigma_{ij}=\sigma_{ji}</math>, and, thus, it has six independent entries.		A positive in the diagonals means that the system is under compressive strain and wants to expand. A negative value implies that the system is under tensile strain and wants to reduce its volume. The stress tensor is symmetric <math>\sigma_{ij}=\sigma_{ji}</math>, and, thus, it has six independent entries.
	The calculation of the stress tensor is relatively time-consuming, and, therefore, by default, it is switched off in some cases (e.g.., hybrid functionals). The forces are always calculated.		The calculation of the stress tensor is relatively time-consuming, and, therefore, by default, it is switched off in some cases (e.g., hybrid functionals). The forces are always calculated.
	{{NB\|tip\|You can get information about the stress at each ionic step using {{TAG\|NWRITE\|0,1,2,3}}.}}		{{NB\|tip\|You can get information about the stress at each ionic step using {{TAG\|NWRITE\|0,1,2,3}}.}}

Csheldon at 11:39, 9 February 2026

2026-02-09T11:39:54Z

← Older revision		Revision as of 11:39, 9 February 2026
Line 12:		Line 12:
	This might be different from other first principles codes.		This might be different from other first principles codes.
	A positive in the diagonals means that the system is under compressive strain and wants to expand. A negative value implies that the system is under tensile strain and wants to reduce its volume. The stress tensor is symmetric <math>\sigma_{ij}=\sigma_{ji}</math>, and, thus, it has six independent entries.		A positive in the diagonals means that the system is under compressive strain and wants to expand. A negative value implies that the system is under tensile strain and wants to reduce its volume. The stress tensor is symmetric <math>\sigma_{ij}=\sigma_{ji}</math>, and, thus, it has six independent entries.
	The calculation of the stress tensor is relatively time-consuming, and, therefore, by default, it is switched off in some cases. The forces are always calculated.		The calculation of the stress tensor is relatively time-consuming, and, therefore, by default, it is switched off in some cases (e.g.., hybrid functionals). The forces are always calculated.
	{{NB\|tip\|You can get information about the stress at each ionic step using {{TAG\|NWRITE\|0,1,2,3}}.}}		{{NB\|tip\|You can get information about the stress at each ionic step using {{TAG\|NWRITE\|0,1,2,3}}.}}

Ftran at 08:58, 26 November 2025

2025-11-26T08:58:09Z

← Older revision		Revision as of 08:58, 26 November 2025
Line 48:		Line 48:
	* Accuracy		* Accuracy
	{{NB\|warning\|The PAW basis for the [[:Category:Electronic minimization\|electronic minimization]] is not adjusted when the structure is varied during a calculation.\|:}}		{{NB\|warning\|The PAW basis for the [[:Category:Electronic minimization\|electronic minimization]] is not adjusted when the structure is varied during a calculation.\|:}}
	:Therefore, carefully consider effects such as [[~~Energy_vs_volume_Volume_relaxations_and~~ Pulay_stress\|Pulay stress]] and choose generous settings for the [[:Category:Electronic minimization\|electronic minimization]]. Generally, volume changes should be done only with an increased energy cutoff, e.g., {{TAG\|ENCUT\|1.3×max({{TAG\|ENMAX}})}}, and {{TAG\|PREC\|High}}.		:Therefore, carefully consider effects such as [[Pulay_stress\|Pulay stress]] and choose generous settings for the [[:Category:Electronic minimization\|electronic minimization]]. Generally, volume changes should be done only with an increased energy cutoff, e.g., {{TAG\|ENCUT\|1.3×max({{TAG\|ENMAX}})}}, and {{TAG\|PREC\|High}}.
	* To further control the ionic degrees of freedom that can vary during the calculation, set `Selective dynamics` in the {{FILE\|POSCAR}} file.		* To further control the ionic degrees of freedom that can vary during the calculation, set `Selective dynamics` in the {{FILE\|POSCAR}} file.
	* {{TAG\|ISIF\|8}} is only available as of VASP.6.4.1.		* {{TAG\|ISIF\|8}} is only available as of VASP.6.4.1.

Singraber at 07:47, 24 October 2025

2025-10-24T07:47:04Z

← Older revision		Revision as of 07:47, 24 October 2025
Line 1:		Line 1:
	{{TAGDEF\|ISIF\|0 {{!}} 1 {{!}} 2 {{!}} 3 {{!}} 4 {{!}} 5 {{!}} 6 {{!}} 7 {{!}} 8}}		{{TAGDEF\|ISIF\|0 {{!}} 1 {{!}} 2 {{!}} 3 {{!}} 4 {{!}} 5 {{!}} 6 {{!}} 7 {{!}} 8}}
	{{DEF\|ISIF\|0\|for {{~~TAGO~~\|IBRION\|0}} (molecular dynamics) or {{~~TAGO~~\|LHFCALC\|.TRUE.}}\|2\|else}}		{{DEF\|ISIF\|0\|for {{TAG\|IBRION\|0}} (molecular dynamics) or {{TAG\|LHFCALC\|.TRUE.}}\|2\|else}}

	Description: Determines if the stress tensor is calculated and which ionic degrees of freedom are varied.		Description: Determines if the stress tensor is calculated and which ionic degrees of freedom are varied.
Line 13:		Line 13:
	A positive in the diagonals means that the system is under compressive strain and wants to expand. A negative value implies that the system is under tensile strain and wants to reduce its volume. The stress tensor is symmetric <math>\sigma_{ij}=\sigma_{ji}</math>, and, thus, it has six independent entries.		A positive in the diagonals means that the system is under compressive strain and wants to expand. A negative value implies that the system is under tensile strain and wants to reduce its volume. The stress tensor is symmetric <math>\sigma_{ij}=\sigma_{ji}</math>, and, thus, it has six independent entries.
	The calculation of the stress tensor is relatively time-consuming, and, therefore, by default, it is switched off in some cases. The forces are always calculated.		The calculation of the stress tensor is relatively time-consuming, and, therefore, by default, it is switched off in some cases. The forces are always calculated.
	{{NB\|tip\|You can get information about the stress at each ionic step using {{~~TAGO~~\|NWRITE\|0,1,2,3}}.}}		{{NB\|tip\|You can get information about the stress at each ionic step using {{TAG\|NWRITE\|0,1,2,3}}.}}

	{{TAG\|ISIF}} also determines which degrees of freedom (ionic positions, cell volume, and cell shape) of the structure are allowed to change.		{{TAG\|ISIF}} also determines which degrees of freedom (ionic positions, cell volume, and cell shape) of the structure are allowed to change.
Line 41:		Line 41:
	\|}		\|}

	* For {{~~TAGO~~\|ISIF\|1}}, only the trace of the stress tensor is calculated. This means only the total pressure is correct and can be read off in the line:		* For {{TAG\|ISIF\|1}}, only the trace of the stress tensor is calculated. This means only the total pressure is correct and can be read off in the line:

	external pressure = ... kB		external pressure = ... kB
Line 48:		Line 48:
	* Accuracy		* Accuracy
	{{NB\|warning\|The PAW basis for the [[:Category:Electronic minimization\|electronic minimization]] is not adjusted when the structure is varied during a calculation.\|:}}		{{NB\|warning\|The PAW basis for the [[:Category:Electronic minimization\|electronic minimization]] is not adjusted when the structure is varied during a calculation.\|:}}
	:Therefore, carefully consider effects such as [[Energy_vs_volume_Volume_relaxations_and Pulay_stress\|Pulay stress]] and choose generous settings for the [[:Category:Electronic minimization\|electronic minimization]]. Generally, volume changes should be done only with an increased energy cutoff, e.g., {{~~TAGO~~\|ENCUT\|1.3×max({{TAG\|ENMAX}})}}, and {{~~TAGO~~\|PREC\|High}}.		:Therefore, carefully consider effects such as [[Energy_vs_volume_Volume_relaxations_and Pulay_stress\|Pulay stress]] and choose generous settings for the [[:Category:Electronic minimization\|electronic minimization]]. Generally, volume changes should be done only with an increased energy cutoff, e.g., {{TAG\|ENCUT\|1.3×max({{TAG\|ENMAX}})}}, and {{TAG\|PREC\|High}}.
	* To further control the ionic degrees of freedom that can vary during the calculation, set `Selective dynamics` in the {{FILE\|POSCAR}} file.		* To further control the ionic degrees of freedom that can vary during the calculation, set `Selective dynamics` in the {{FILE\|POSCAR}} file.
	* {{~~TAGO~~\|ISIF\|8}} is only available as of VASP.6.4.1.		* {{TAG\|ISIF\|8}} is only available as of VASP.6.4.1.
	== Related tags and articles ==		== Related tags and articles ==
	{{TAG\|IBRION}},		{{TAG\|IBRION}},

Csheldon at 11:52, 20 October 2025

2025-10-20T11:52:24Z

← Older revision		Revision as of 11:52, 20 October 2025
Line 55:		Line 55:
	[[structure optimization]],		[[structure optimization]],
	[[:Category:Ensembles\| Ensembles]],		[[:Category:Ensembles\| Ensembles]],
			{{TAG\|NWRITE}},
	Selective-dynamics mode of the {{FILE\|POSCAR}} file,		Selective-dynamics mode of the {{FILE\|POSCAR}} file,
	{{TAG\|LATTICE_CONSTRAINTS}}		{{TAG\|LATTICE_CONSTRAINTS}}

Csheldon at 11:51, 20 October 2025

2025-10-20T11:51:49Z

← Older revision		Revision as of 11:51, 20 October 2025
Line 13:		Line 13:
	A positive in the diagonals means that the system is under compressive strain and wants to expand. A negative value implies that the system is under tensile strain and wants to reduce its volume. The stress tensor is symmetric <math>\sigma_{ij}=\sigma_{ji}</math>, and, thus, it has six independent entries.		A positive in the diagonals means that the system is under compressive strain and wants to expand. A negative value implies that the system is under tensile strain and wants to reduce its volume. The stress tensor is symmetric <math>\sigma_{ij}=\sigma_{ji}</math>, and, thus, it has six independent entries.
	The calculation of the stress tensor is relatively time-consuming, and, therefore, by default, it is switched off in some cases. The forces are always calculated.		The calculation of the stress tensor is relatively time-consuming, and, therefore, by default, it is switched off in some cases. The forces are always calculated.
			{{NB\|tip\|You can get information about the stress at each ionic step using {{TAGO\|NWRITE\|0,1,2,3}}.}}

	{{TAG\|ISIF}} also determines which degrees of freedom (ionic positions, cell volume, and cell shape) of the structure are allowed to change.		{{TAG\|ISIF}} also determines which degrees of freedom (ionic positions, cell volume, and cell shape) of the structure are allowed to change.

Schlipf: /* Related tags and articles */

2024-10-18T11:49:15Z

← Older revision		Revision as of 11:40, 9 February 2026
Line 49:		Line 49:
	{{NB\|warning\|The PAW basis for the [[:Category:Electronic minimization\|electronic minimization]] is not adjusted when the structure is varied during a calculation.\|:}}		{{NB\|warning\|The PAW basis for the [[:Category:Electronic minimization\|electronic minimization]] is not adjusted when the structure is varied during a calculation.\|:}}
	:Therefore, carefully consider effects such as [[Pulay_stress\|Pulay stress]] and choose generous settings for the [[:Category:Electronic minimization\|electronic minimization]]. Generally, volume changes should be done only with an increased energy cutoff, e.g., {{TAG\|ENCUT\|1.3×max({{TAG\|ENMAX}})}}, and {{TAG\|PREC\|High}}.		:Therefore, carefully consider effects such as [[Pulay_stress\|Pulay stress]] and choose generous settings for the [[:Category:Electronic minimization\|electronic minimization]]. Generally, volume changes should be done only with an increased energy cutoff, e.g., {{TAG\|ENCUT\|1.3×max({{TAG\|ENMAX}})}}, and {{TAG\|PREC\|High}}.
	* To further control the ionic degrees of freedom that can vary during the calculation, set `Selective dynamics` in the {{FILE\|POSCAR}} file.		* To further control the ionic degrees of freedom that can vary during the calculation, set <code>Selective dynamics</code> in the {{FILE\|POSCAR}} file.
	* {{TAG\|ISIF\|8}} is only available as of VASP.6.4.1.		* {{TAG\|ISIF\|8}} is only available as of VASP.6.4.1.
	== Related tags and articles ==		== Related tags and articles ==

← Older revision		Revision as of 08:58, 26 November 2025
Line 48:		Line 48:
	* Accuracy		* Accuracy
	{{NB\|warning\|The PAW basis for the [[:Category:Electronic minimization\|electronic minimization]] is not adjusted when the structure is varied during a calculation.\|:}}		{{NB\|warning\|The PAW basis for the [[:Category:Electronic minimization\|electronic minimization]] is not adjusted when the structure is varied during a calculation.\|:}}
	:Therefore, carefully consider effects such as [[~~Energy_vs_volume_Volume_relaxations_and~~ Pulay_stress\|Pulay stress]] and choose generous settings for the [[:Category:Electronic minimization\|electronic minimization]]. Generally, volume changes should be done only with an increased energy cutoff, e.g., {{TAG\|ENCUT\|1.3×max({{TAG\|ENMAX}})}}, and {{TAG\|PREC\|High}}.		:Therefore, carefully consider effects such as [[Pulay_stress\|Pulay stress]] and choose generous settings for the [[:Category:Electronic minimization\|electronic minimization]]. Generally, volume changes should be done only with an increased energy cutoff, e.g., {{TAG\|ENCUT\|1.3×max({{TAG\|ENMAX}})}}, and {{TAG\|PREC\|High}}.
	* To further control the ionic degrees of freedom that can vary during the calculation, set `Selective dynamics` in the {{FILE\|POSCAR}} file.		* To further control the ionic degrees of freedom that can vary during the calculation, set `Selective dynamics` in the {{FILE\|POSCAR}} file.
	* {{TAG\|ISIF\|8}} is only available as of VASP.6.4.1.		* {{TAG\|ISIF\|8}} is only available as of VASP.6.4.1.

← Older revision		Revision as of 11:52, 20 October 2025
Line 55:		Line 55:
	[[structure optimization]],		[[structure optimization]],
	[[:Category:Ensembles\| Ensembles]],		[[:Category:Ensembles\| Ensembles]],
			{{TAG\|NWRITE}},
	Selective-dynamics mode of the {{FILE\|POSCAR}} file,		Selective-dynamics mode of the {{FILE\|POSCAR}} file,
	{{TAG\|LATTICE_CONSTRAINTS}}		{{TAG\|LATTICE_CONSTRAINTS}}

← Older revision		Revision as of 11:49, 18 October 2024
Line 52:		Line 52:
	== Related tags and articles ==		== Related tags and articles ==
	{{TAG\|IBRION}},		{{TAG\|IBRION}},
			[[structure optimization]],
	[[:Category:Ensembles\| Ensembles]],		[[:Category:Ensembles\| Ensembles]],
	Selective-dynamics mode of the {{FILE\|POSCAR}} file,		Selective-dynamics mode of the {{FILE\|POSCAR}} file,