A COMBINATION OF THE WORK FORMALISM FOR EXCHANGE WITH AN OPTIMIZED CORRELATION-ENERGY FUNCTIONAL FOR ATOMS

The Harbola-Sahni formalism for the exchange potential of many-electron systems gives extremely accurate total energies for atoms (the energies are practically indistinguishable from the Hartree-Fock energies). We combine here this formalism with the usual density functional prescription for the correlation potential, using a recently developed optimized local correlation functional (Gritsenko O.V. et al., Phys. Rev. A 47 (1993) 1811). Numerical tests carried out for several closed shell atoms and ions indicate that the results preserve the accuracy of the exchange-only calculations. We expect the same behavior to hold true for large molecules and atomic clusters. However, similar tests for the He, Be and Ne isoelectronic series indicate that the optimized local correlation functional is not valid for highly ionized atoms.