Ensemble density functional theory with spherically symmetric densities

Abstract

The spherical ensemble theory of excited states is developed. The Hohenberg–Kohn theorems are extended to ensembles with spherically symmetric densities via constrained search, and spherical ensemble Kohn–Sham-like equations are derived. The spherical ensemble theory makes it possible to apply a different partition of the energy functional. The spherical Hartree expression is generalized to ensembles. An exactly soluble model of a harmonic two-electron molecule is analyzed.