LNOAUGXC: Difference between revisions
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Description: {{TAG|LNOAUGXC}} specifies if a {{TAG|METAGGA}} functional is evaluated with a density that is augmented or not. | Description: {{TAG|LNOAUGXC}} specifies if a {{TAG|METAGGA}} functional is evaluated with a density that is augmented or not. | ||
---- | ---- | ||
{{NB|deprecated|The {{TAG|LNOAUGXC}} tag is obsolete and should not be used.}} | |||
The Kohn-Sham kinetic-energy density | The Kohn-Sham kinetic-energy density | ||
:<math>\tau_{\sigma}=\frac{1}{2}\sum_{i}\nabla\psi_{i\sigma}^{*}\cdot\nabla\psi_{i\sigma}</math> | :<math>\tau_{\sigma}=\frac{1}{2}\sum_{i}\nabla\psi_{i\sigma}^{*}\cdot\nabla\psi_{i\sigma}</math> | ||
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However, this may not always be the case, particularly within the PAW spheres, when the pseudo density is augmented with the compensation charge. If {{TAG|LNOAUGXC}}=.TRUE. is set in the {{FILE|INCAR}} file, then the pseudo density is not augmented, which should alleviate the breaking of the condition <math>\tau_{\sigma}^{\textrm{W}}<\tau_{\sigma}</math>. | However, this may not always be the case, particularly within the PAW spheres, when the pseudo density is augmented with the compensation charge. If {{TAG|LNOAUGXC}}=.TRUE. is set in the {{FILE|INCAR}} file, then the pseudo density is not augmented, which should alleviate the breaking of the condition <math>\tau_{\sigma}^{\textrm{W}}<\tau_{\sigma}</math>. | ||
A violation of <math>\tau_{\sigma}^{\textrm{W}}<\tau_{\sigma}</math> can make the calculations unstable | A violation of <math>\tau_{\sigma}^{\textrm{W}}<\tau_{\sigma}</math> can make the calculations unstable depending on the meta-GGA functional. | ||
{{NB|mind| | {{NB|mind| | ||
*This tag is available since VASP.6.5.0 and is a replacement of the compiler option [[Precompiler options#-DnoAugXCmeta|-DnoAugXCmeta]] that was available until VASP.6.4.3. | *This tag is available since VASP.6.5.0 and is a replacement of the compiler option [[Precompiler options#-DnoAugXCmeta|-DnoAugXCmeta]] that was available until VASP.6.4.3. | ||
*This option may negatively affect the results, therefore it should be used only for functionals | *This option may negatively affect the results, therefore it should be used only for functionals for which the breaking of the condition <math>\tau_{\sigma}^{\textrm{W}}<\tau_{\sigma}</math> may lead to numerical problems.}} | ||
== Related tags and articles == | == Related tags and articles == | ||
{{TAG|METAGGA}}, | {{TAG|METAGGA}}, | ||
Revision as of 08:22, 17 August 2026
LNOAUGXC = .TRUE. | .FALSE.
Default: LNOAUGXC = .FALSE.
Description: LNOAUGXC specifies if a METAGGA functional is evaluated with a density that is augmented or not.
| Deprecated: The LNOAUGXC tag is obsolete and should not be used. |
The Kohn-Sham kinetic-energy density
- [math]\displaystyle{ \tau_{\sigma}=\frac{1}{2}\sum_{i}\nabla\psi_{i\sigma}^{*}\cdot\nabla\psi_{i\sigma} }[/math]
should, in principle, be larger than the von Weizsäcker kinetic-energy density[1]
- [math]\displaystyle{ \tau_{\sigma}^{\textrm{W}}=\frac{\left\vert\nabla n_{\sigma}\right\vert^{2}}{8 n_{\sigma}}. }[/math]
However, this may not always be the case, particularly within the PAW spheres, when the pseudo density is augmented with the compensation charge. If LNOAUGXC=.TRUE. is set in the INCAR file, then the pseudo density is not augmented, which should alleviate the breaking of the condition [math]\displaystyle{ \tau_{\sigma}^{\textrm{W}}<\tau_{\sigma} }[/math].
A violation of [math]\displaystyle{ \tau_{\sigma}^{\textrm{W}}<\tau_{\sigma} }[/math] can make the calculations unstable depending on the meta-GGA functional.
Mind:
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