Adiabatic Connection and the Kohn-Sham Variety of Potential-Functional Theory.

Abstract

In potential−functional theory the total electronic energy is expressed as a functional of the external potential. We discuss how approximations, Tsapp[v], of the noninteracting kinetic energy functional can be exploited for interacting systems. Two possibilities are discussed: (a) Via an adiabatic connection formula, Tsapp[v0] can be used directly with the external potential v0 of the interacting system, and (b) by employing the variational principle of density functional theory, the kinetic energy functional Tsapp[vs] is evaluated at the Kohn−Sham potential vs, which, in turn, is determined by an iterative procedure. Advantages and disadvantages of the two approaches are discussed.