VRijkl: Difference between revisions

Revision as of 08:00, 28 March 2025

This file is written for ALGO=2e4wa and stores all off-centre Coulomb integrals commensurate with the selected k-point grid

{\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}'|} }

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 selected with DMFT_BASIS.

Evaluation of Coulomb integrals can be computationally demanding if the number of basis functions becomes large.

Tip: Use a coarser sub-grid of the original k-point grid with LDOWNSAMPLE for speed up.

Mind: Available as of VASP.6.5.2.

@@ Line 1: / Line 1: @@
-This file stores the off-centre Coulomb integrals
+This file is written for {{TAG|ALGO}}=2e4wa and stores all off-centre Coulomb integrals
+commensurate with the selected k-point grid
 ::<math>
 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>
 The format is as follows:
   # V_ijkl = [ij,R|kl,0]
@@ Line 15: / Line 16: @@
    1   1   1        0.0617934919       -0.0000371600
    ...
+A proper {{FILE|WAVECAR}} file must be present in the working directory. The basis can be selected with {{TAG|DMFT_BASIS}}.
+Evaluation of Coulomb integrals can be computationally demanding if the number of basis functions becomes large.
+{{NB|tip|Use a coarser sub-grid of the original k-point grid with {{TAG|LDOWNSAMPLE}} for speed up.}}
 {{NB|mind|Available as of VASP.6.5.2.}}
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 [[Category:Files]][[Category:Output files]][[Category:Constrained-random-phase approximation]]