Optimized Effective Potential Method and KLI Approximation for Systems with Degenerate Orbitals in the LCAO Calculations

Abstract

A new formulation of the optimized effective potential (OEP) method is presented. Our OEP method is applicable to the linear combination of atomic orbital (LCAO) calculation for systems which have degenerate orbitals, in contrast to the conventional OEP method. An approximation to our OEP equation for the exchange-correlation (xc) potential, similar to the KLI approximation, is derived.