VRijkl: Difference between revisions
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{{Available|6.6.0}} | {{Available|6.6.0}} | ||
The {{FILE|VRijkl}} file is written for {{TAG|ALGO|2e4wa}} and stores all bare off-center Coulomb integrals commensurate with the selected k-point grid (see [[Constrained–random-phase–approximation formalism#Off-center interactions|off-center interactions]]): | |||
commensurate with the selected k-point grid | |||
::<math> | ::<math> | ||
V_{ijkl}^{\sigma\sigma'} = \int {\rm d}{\bf r}\int {\rm d}{\bf r}' | V_{ijkl}^{\sigma\sigma'} = \int {\rm d}{\bf r}\int {\rm d}{\bf r}' | ||
\frac{ w_{i}^{*\sigma}({\bf r}) w_{j}^{\sigma}({\bf r}) w_{k}^{*\sigma'}({\bf r}'+{\bf R}) w_{l}^{\sigma'}({\bf r}'+{\bf R})}{|{\bf r}-{\bf r}'|} | \frac{ w_{i}^{*\sigma}({\bf r}) w_{j}^{\sigma}({\bf r}) w_{k}^{*\sigma'}({\bf r}'+{\bf R}) w_{l}^{\sigma'}({\bf r}'+{\bf R})}{|{\bf r}-{\bf r}'|} | ||
</math> | </math> | ||
The format is as follows: | The file contains one block per lattice vector '''R'''. Each block header gives the lattice vector index and its fractional coordinates. The columns I, J, K, L are the Wannier function indices; RE and IM are the real and imaginary parts. The format is as follows: | ||
# V_ijkl = [ij,R|kl,0] | |||
# I J K L RE(V_IJKL) IM(V_IJKL) | |||
# R: 1 0.000000 0.000000 0.000000 | |||
1 1 1 1 14.4576272582 0.0000000000 | |||
2 1 1 1 0.0000010313 0.0000031049 | |||
... | |||
# R: 2 0.000000 0.000000 1.000000 | |||
1 1 1 1 4.6546536926 0.0000000000 | |||
2 1 1 1 0.0617934919 -0.0000371600 | |||
... | |||
A proper {{FILE|WAVECAR}} file must be present in the working directory. The basis can be | A proper {{FILE|WAVECAR}} file must be present in the working directory. The basis can be specified using {{TAG|LOCALIZED_BASIS}} tag. | ||
Evaluation of Coulomb integrals can be computationally demanding if the number of basis functions becomes large. | |||
{{NB|tip|To improve performance, use a coarser sub-grid of the original '''k'''-point grid by enabling {{TAG|LDOWNSAMPLE|T}}.}} | |||
== Related tags and articles == | |||
[[Constrained–random-phase–approximation formalism]] | |||
Files: {{FILE|VIJKL}}, {{FILE|UIJKL}}, {{FILE|URijkl}} | |||
Tags: {{TAG|LTWO_CENTER}}, {{TAG|LOCALIZED_BASIS}}, {{TAG|ALGO}} | |||
[[Category:Files]][[Category:Output files]][[Category:Constrained-random-phase approximation]] | [[Category:Files]][[Category:Output files]][[Category:Constrained-random-phase approximation]] | ||
Latest revision as of 10:50, 20 March 2026
| Mind: Available as of VASP 6.6.0 |
The VRijkl file is written for ALGO = 2e4wa and stores all bare off-center Coulomb integrals commensurate with the selected k-point grid (see off-center interactions):
- [math]\displaystyle{ V_{ijkl}^{\sigma\sigma'} = \int {\rm d}{\bf r}\int {\rm d}{\bf r}' \frac{ w_{i}^{*\sigma}({\bf r}) w_{j}^{\sigma}({\bf r}) w_{k}^{*\sigma'}({\bf r}'+{\bf R}) w_{l}^{\sigma'}({\bf r}'+{\bf R})}{|{\bf r}-{\bf r}'|} }[/math]
The file contains one block per lattice vector R. Each block header gives the lattice vector index and its fractional coordinates. The columns I, J, K, L are the Wannier function indices; RE and IM are the real and imaginary parts. The format is as follows:
# V_ijkl = [ij,R|kl,0]
# I J K L RE(V_IJKL) IM(V_IJKL)
# R: 1 0.000000 0.000000 0.000000
1 1 1 1 14.4576272582 0.0000000000
2 1 1 1 0.0000010313 0.0000031049
...
# R: 2 0.000000 0.000000 1.000000
1 1 1 1 4.6546536926 0.0000000000
2 1 1 1 0.0617934919 -0.0000371600
...
A proper WAVECAR file must be present in the working directory. The basis can be specified using LOCALIZED_BASIS tag.
Evaluation of Coulomb integrals can be computationally demanding if the number of basis functions becomes large.
Tip: To improve performance, use a coarser sub-grid of the original k-point grid by enabling LDOWNSAMPLE = T.
|
Related tags and articles
Constrained–random-phase–approximation formalism
Tags: LTWO_CENTER, LOCALIZED_BASIS, ALGO