Constrained optimized potential method and second‐order correlation energy for excited states

Abstract

AbstractAn optimized effective potential (OEP) approach based on density functional theory for individual excited states and a simple to implement method which takes the orthogonality constraints into account (TOCIA) for the Kohn–Sham determinants is developed with the aim of constructing the orbital‐dependent correlation energy corrections. It is shown that the TOCIA methodology makes it possible to apply both the OEP experience and the perturbative second‐order correction for the ground state to the excited state problem with the same computational effort. A performance of the proposed method is demonstrated by calculations of excitation energies for the Li atom and HeH and LiHe molecules at the different levels of approximation. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007