The optimized effective potential method of density functional theory: Applications to atomic and molecular systems

Using the optimized effective potential method in conjunction with the semianalytical approximation due to Krieger, Li, and Iafrate, we performed fully self-consistent exact exchange-only density functional calculations for diatomic molecules with a fully numerical basis-set-free molecular code. The results are very similar to the ones obtained with the Hartree-Fock approach. Furthermore, we present results for ground states of positive atomic ions including correlation contributions in the approximation of Colle and Salvetti. It is found that the scheme performs significantly better than do conventional Kohn-Sham calculations.