Modeling the Kohn-Sham potential for molecular dissociation with orbital-independent functionals: A proof of principle.

Abstract

We model the Hartree-exchange-correlation potential of Kohn-Sham (KS) density-functional theory adopting a novel strategy inspired by the strictly correlated-electron limit and relying on the exact decomposition of the potential based on the exact factorization formalism. Starting with accurate density and conditional potential for a one-dimensional model of a stretched heteronuclear molecule, we provide a proof-of-principle example of an approximation that accurately reproduces the step of the exact KS potential without resorting to the KS orbitals, virtual or occupied. We also test our strategy using the approximate conditional potentials corresponding to the strictly correlated-electron and the exact-exchange functionals. The results are encouraging in that the initial approximations are modified in the qualitatively correct way: decreasing correlation in the former and increasing it in the latter.