LTBOUNDLIBXC: Difference between revisions

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[[Category:INCAR]][[Category:XC Functionals]][[Category:metaGGA]]
[[Category:INCAR]][[Category:Exchange-correlation functionals]][[Category:metaGGA]]

Revision as of 07:59, 6 April 2022

LTBOUNDLIBXC = .TRUE. | .FALSE.
Default: LTBOUNDLIBXC = .FALSE. 

Description: LTBOUNDLIBXC specifies whether or not the lower bound for the Kohn-Sham kinetic-energy density () is enforced before is used in a meta-GGA functional from Libxc.


The KS kinetic-energy density should in principle be larger than the von Weizsäcker kinetic-energy density . However, for numerical reasons this may not always be the case and can potentially lead to problems depending on the meta-GGA. If LTBOUNDLIBXC=.TRUE. in INCAR, then is applied before is used in a meta-GGA functional from Libxc.

However, according to tests, for some of the most common meta-GGA functionals like SCAN[1], a violation of the lower bound is technically not a problem and, furthermore, applying leads to very inaccurate forces and stress tensor. Therefore, by default LTBOUNDLIBXC=.FALSE. and Libxc should be compiled with the option --disable-fhc has explained here.

Related Tags and Sections

LIBXC1, LIBXC2, METAGGA


Examples that use this tag

References