LNOAUGXC

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

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

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The Kohn-Sham kinetic-energy density [math]\displaystyle{ \tau_{\sigma} }[/math] should in principle be larger than the von Weizsäcker kinetic-energy density [math]\displaystyle{ \tau_{\sigma}^{\textrm{W}}=\left\vert\nabla\rho_{\sigma}\right\vert^{2}/\left(8\rho_{\sigma}\right) }[/math]. 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 [math]\displaystyle{ \tau_{\sigma}^{\textrm{W}}\lt \tau_{\sigma} }[/math].

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

Mind: 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 [math]\displaystyle{ \tau_{\sigma}^{\textrm{W}}\lt \tau_{\sigma} }[/math] leads to numerical problems.

See LTBOUNDLIBXC for a related tag.

Related tags and articles

METAGGA, LTBOUNDLIBXC

Examples that use this tag

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