THE OPTIMIZED EFFECTIVE POTENTIAL FOR ATOMS AND SEMICONDUCTORS

Abstract

Given an n-electron Hamiltonian containing a potential operator such as the Fock operator, the optimized effective potential (OEP) is that simple multiplicative potential whose n lowest eigenfunctions minimize the expectation value of the Hamiltonian. Thus it is the exact Kohn-Sham potential for that Hamiltonian. We discuss OEP calculations and the KLI approximation to it for atoms and semiconductors. Because the Fock operator treats exchange exactly, all deviations from experimental energies are attributable to the use of approximate correlation energy density functionals whose shortcomings are discussed.