Exact-exchange extension of the local-spin-density approximation in atoms: Calculation of total energies and electron affinities

Total energies and electron affinities of selected atoms are calculated in a local-spin-density scheme where the exchange is treated exactly. A much improved overall description of the electronic structure is obtained with respect to the usual Hartree–Fock and local-spin-density approximations. The joint use of the exact expression for the exchange and of the local approximation for the correlation gives much better total energies and allows to avoid the failures of the above two schemes in the calculation of negative-ion binding energies. The accuracy for total energies of first and second row atoms is better than 2 eV, while the typical error for electron affinities is 0.2 eV.