LTWO CENTER: Difference between revisions
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{{TAGDEF|LTWO_CENTER|[logical]|.FALSE.}} | {{TAGDEF|LTWO_CENTER|[logical]|.FALSE.}} | ||
{{DISPLAYTITLE:LTWO_CENTER}} | |||
Description: {{TAG|LTWO_CENTER}} calculates off-center [[Constrained–random-phase–approximation_formalism# | Description: {{TAG|LTWO_CENTER}} calculates off-center [[Constrained–random-phase–approximation_formalism#Off-center_interactions|Coulomb integrals]]. | ||
---- | ---- | ||
When chosen, the system calculates two types of integrals: | When chosen, the system calculates two types of integrals: | ||
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U(R) = \frac{U(R=0)}{\sqrt{\frac{R}\delta + 1}} | U(R) = \frac{U(R=0)}{\sqrt{\frac{R}\delta + 1}} | ||
</math> | </math> | ||
<syntaxhighlight lang="python"> | |||
import py4vasp as pv | |||
== Related tags and articles== | calc = pv.Calculation.from_path(".") | ||
calc.effective_coulomb.plot(selection="U V", radius=...) | |||
</syntaxhighlight> | |||
The above plots the spatial decay of the Coulomb interaction and fits the Ohno potential to the off-center integrals. Using <code>radius=...</code> passes the radial grid directly from the VASP output. | |||
{{Available|6.6.0}} | |||
== Related tags and articles == | |||
{{FILE|VRijkl}}, | |||
{{FILE|URijkl}}, | |||
{{TAG|LDISENTANGLED}}, | {{TAG|LDISENTANGLED}}, | ||
{{TAG|LWEIGHTED}}, | {{TAG|LWEIGHTED}}, | ||
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{{TAG|ALGO}} | {{TAG|ALGO}} | ||
{{sc|LTWO_CENTER|Howto| | {{sc|LTWO_CENTER|Howto|Workflows that use this tag}} | ||
== References == | == References == | ||
<references/> | <references/> | ||
[[Category:INCAR_tag]][[Category:Constrained-random-phase approximation]] | [[Category:INCAR_tag]][[Category:Constrained-random-phase approximation]] | ||
Latest revision as of 10:09, 20 March 2026
LTWO_CENTER = [logical]
Default: LTWO_CENTER = .FALSE.
Description: LTWO_CENTER calculates off-center Coulomb integrals.
When chosen, the system calculates two types of integrals:
- Bare integrals (stored in VRijkl)
- [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]
- Effectively screened integrals (stored in URijkl)
- [math]\displaystyle{ U_{ijkl}^{\sigma\sigma'} = \int {\rm d}{\bf r}\int {\rm d}{\bf r}' w_{i}^{*\sigma}({\bf r}) w_{j}^{\sigma}({\bf r}) U({\bf r},{\bf r}',\omega) w_{k}^{*\sigma'}({\bf r}'+{\bf R}) w_{l}^{\sigma'}({\bf r}'+{\bf R}) }[/math]
When chosen, cRPA matrix elements in vaspout.h5 can be used with py4vasp to analyze the spatial decay of the Coulomb interaction using the Ohno potential[1]
[math]\displaystyle{ U(R) = \frac{U(R=0)}{\sqrt{\frac{R}\delta + 1}} }[/math]
import py4vasp as pv
calc = pv.Calculation.from_path(".")
calc.effective_coulomb.plot(selection="U V", radius=...)
The above plots the spatial decay of the Coulomb interaction and fits the Ohno potential to the off-center integrals. Using radius=... passes the radial grid directly from the VASP output.
| Mind: Available as of VASP 6.6.0 |
Related tags and articles
VRijkl, URijkl, LDISENTANGLED, LWEIGHTED, LSCRPA, ALGO