LNOAUGXC: Difference between revisions

From VASP Wiki
No edit summary
No edit summary
Line 4: Line 4:
----
----


The Kohn-Sham kinetic-energy density <math>\tau_{\sigma}=\frac{1}{2}\sum_{i}\nabla\psi_{i}^{*}\nabla\psi_{i}</math> should in principle be larger than the von Weizsäcker kinetic-energy density <math>\tau_{\sigma}^{\textrm{W}}=\left\vert\nabla\rho_{\sigma}\right\vert^{2}/\left(8\rho_{\sigma}\right)</math>.{{cite|kurth:ijqc:1999}} However, this may not be always the case, in particular within the PAW spheres when the pseudo density is augmented with the compensation charge. If {{TAG|LNOAUGXC}}=.TRUE. in {{FILE|INCAR}}, then the pseudo density is not augmented, which should alleviate the breaking of the condition <math>\tau_{\sigma}^{\textrm{W}}<\tau_{\sigma}</math>.
The Kohn-Sham kinetic-energy density <math>\tau_{\sigma}=(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 <math>\tau_{\sigma}^{\textrm{W}}=\left\vert\nabla\rho_{\sigma}\right\vert^{2}/\left(8\rho_{\sigma}\right)</math>.{{cite|kurth:ijqc:1999}} However, this may not be always the case, in particular within the PAW spheres when the pseudo density is augmented with the compensation charge. If {{TAG|LNOAUGXC}}=.TRUE. in {{FILE|INCAR}}, then the pseudo density is not augmented, which should alleviate the breaking of the condition <math>\tau_{\sigma}^{\textrm{W}}<\tau_{\sigma}</math>.


Not having <math>\tau_{\sigma}^{\textrm{W}}<\tau_{\sigma}</math> satisfied can make the calculations unstable, in particular with the TPSS family of functionals.
Not having <math>\tau_{\sigma}^{\textrm{W}}<\tau_{\sigma}</math> satisfied can make the calculations unstable, in particular with the TPSS family of functionals.

Revision as of 07:33, 11 June 2024

LNOAUGXC = .TRUE. | .FALSE.
Default: LNOAUGXC = .FALSE. 

Description: LNOAUGXC specifies if a METAGGA exchange-correlation functional is evaluated with a density that is augmented or not.


The Kohn-Sham kinetic-energy density should in principle be larger than the von Weizsäcker kinetic-energy density .[1] However, this may not be always the case, in particular within the PAW spheres when the pseudo density is augmented with the compensation charge. If LNOAUGXC=.TRUE. in INCAR, then the pseudo density is not augmented, which should alleviate the breaking of the condition .

Not having satisfied can make the calculations unstable, in particular with the TPSS family of functionals.

Mind:
  • This tag is available since VASP.6.5.0 and is a replacement of the compiler option -DnoAugXCmeta that was available until VASP.6.4.3.
  • This option may negatively affect the results, therefore it should be used only for functionals, e.g. TPSS, for which the breaking of the condition may lead to numerical problems.

See LTBOUNDLIBXC for a related tag.

Related tags and articles

METAGGA, LTBOUNDLIBXC

Examples that use this tag

References