Title: Deorbitalization strategies for meta-GGA exchange-correlation functionals,
Abstract: We explore the simplification of widely used meta-generalized-gradient
approximation (mGGA) exchange-correlation functionals to the Laplacian level of
refinement by use of approximate kinetic energy density functionals (KEDFs).
Such deorbitalization is motivated by the prospect of reducing computational
cost while recovering a strictly Kohn-Sham local potential framework (rather
than the usual generalized Kohn-Sham treatment of mGGAs). A KEDF that has been
rather successful in solid simulations proves to be inadequate for
deorbitalization but we produce other forms which, with parametrization to
Kohn-Sham results (not experimental data) on a small training set, yield rather
good results on standard molecular test sets when used to deorbitalize the
meta-GGA made very simple, TPSS, and SCAN functionals. We also study the
difference between high-fidelity and best-performing deorbitalizations and
discuss possible implications for use in ab initio molecular dynamics
simulations of complicated condensed phase systems.