title: Ground-state energy as a simple sum of orbital energies in Kohn-Sham theory: a shift in perspective through a shift in potential.
abstract: It is observed that the exact interacting ground-state electronic energy of interest may be obtained directly, in principle, as a simple sum of orbital energies when a universal density-dependent term is added to w([ρ];r), the familiar Hartree plus exchange-correlation component in the Kohn-Sham effective potential. The resultant shifted potential, w[over ¯]([ρ];r), actually changes less on average than w([ρ];r) when the density changes, including the fact that w[over ¯]([ρ];r) does not undergo a discontinuity when the number of electrons increases through an integer. Thus, the approximation of w[over ¯]([ρ];r) represents an alternative direct approach for the approximation of the ground-state energy and density.
authors.affiliation: Department of Chemistry, Duke University, Durham, North Carolina 27708, USA and Department of Physics, North Carolina A&T State University, Greensboro, North Carolina 27411, USA and Department of Chemistry and Quantum Theory Group, Tulane University, New Orleans, Louisiana 70118, USA.
authors.forename: Mel
authors.initials: M
authors.lastname: Levy
authors.affiliation: Department of Chemistry and Ames Laboratory, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Federico
authors.initials: F
authors.lastname: Zahariev