SPRING K: Difference between revisions
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{{TAGDEF|SPRING_K|[real (array)]}} | {{TAGDEF|SPRING_K|[real (array)]}} | ||
Description: The parameter {{TAG|SPRING_K}} defines force constants (<math>\kappa_{\mu} | Description: Force constant for harmonic bias potential. | ||
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The parameter {{TAG|SPRING_K}} defines force constants (<math>\kappa_{\mu}</math>) for the harmonic bias of the following form: | |||
<math> | ::<math> | ||
\tilde{V}(\xi_1,\dots,\xi_{M_8}) = \sum_{\mu=1}^{M}\frac{1}{2}\kappa_{\mu} (\xi_{\mu}(q)-\xi_{0\mu})^2 \; | \tilde{V}(\xi_1,\dots,\xi_{M_8}) = \sum_{\mu=1}^{M}\frac{1}{2}\kappa_{\mu} (\xi_{\mu}(q)-\xi_{0\mu})^2 \; | ||
</math> | </math> | ||
where the sum runs over all (<math>M_8</math>) coordinates | where the sum runs over all (<math>M_8</math>) coordinates the potential acts upon (<math>\xi_{\mu}(q)</math>), which are defined in the {{FILE|ICONST}} file by setting the <code>status</code> to 8. | ||
The units of <math>\kappa_{\mu}</math> are <math>eV/uc</math> where <math>uc</math> units of coordinate the potential acts upon (e.g., <math>{\AA}</math> for coordinates with <code>flag</code> R, <math>rad.</math> for coordinates with <code>flag</code> A, dimensionless for coordinates with <code>flag</code> W, etc...) | The units of <math>\kappa_{\mu}</math> are <math>eV/uc</math> where <math>uc</math> units of coordinate the potential acts upon (e.g., <math>{\AA}</math> for coordinates with <code>flag</code> R, <math>rad.</math> for coordinates with <code>flag</code> A, dimensionless for coordinates with <code>flag</code> W, etc...) | ||
The number of items defined via {{TAG|SPRING_K}} must be equal to <math>M_8</math>, otherwise the calculation terminates with an error message. | The number of items defined via {{TAG|SPRING_K}} must be equal to <math>M_8</math>, otherwise the calculation terminates with an error message. | ||
== Related tags and articles == | == Related tags and articles == | ||
{{TAG|SPRING_R0}} | {{TAG|SPRING_R0}}, | ||
{{TAG|SPRING_V0}} | {{TAG|SPRING_V0}}, | ||
{{FILE|ICONST}} | {{FILE|ICONST}}, | ||
{{TAG|Biased molecular dynamics}} | {{TAG|Biased molecular dynamics}} | ||
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[[Category:INCAR tag]][[Category:Advanced molecular-dynamics sampling]] | |||
Latest revision as of 13:40, 7 March 2025
SPRING_K = [real (array)]
Description: Force constant for harmonic bias potential.
The parameter SPRING_K defines force constants ([math]\displaystyle{ \kappa_{\mu} }[/math]) for the harmonic bias of the following form:
- [math]\displaystyle{ \tilde{V}(\xi_1,\dots,\xi_{M_8}) = \sum_{\mu=1}^{M}\frac{1}{2}\kappa_{\mu} (\xi_{\mu}(q)-\xi_{0\mu})^2 \; }[/math]
where the sum runs over all ([math]\displaystyle{ M_8 }[/math]) coordinates the potential acts upon ([math]\displaystyle{ \xi_{\mu}(q) }[/math]), which are defined in the ICONST file by setting the status to 8.
The units of [math]\displaystyle{ \kappa_{\mu} }[/math] are [math]\displaystyle{ eV/uc }[/math] where [math]\displaystyle{ uc }[/math] units of coordinate the potential acts upon (e.g., [math]\displaystyle{ {\AA} }[/math] for coordinates with flag R, [math]\displaystyle{ rad. }[/math] for coordinates with flag A, dimensionless for coordinates with flag W, etc...)
The number of items defined via SPRING_K must be equal to [math]\displaystyle{ M_8 }[/math], otherwise the calculation terminates with an error message.
Related tags and articles
SPRING_R0, SPRING_V0, ICONST, Biased molecular dynamics