PSTRESS: Difference between revisions
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{{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. | ||
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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 | {{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}} | ||
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[[Category:INCAR]][[Category: Molecular | [[Category:INCAR tag]][[Category: Molecular dynamics]][[Category:Ensembles]][[Category:Ionic minimization]][[Category:Forces]] | ||
Revision as of 08:34, 7 April 2022
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.
If the PSTRESS tag is specified VASP will add this pressure to the diagonals of the stress tensor and add an energy term to the energy. This allows the user to converge to a specified external pressure.
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 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 Energy vs volume Volume relaxations and Pulay stress
In molecular-dynamics calculations within the NpT ensemble this tag controls the target pressure. The unit of PSTRESS is in kB.