New correlation potential for the local-spin-density functional formalism I. Total energies and ionization potentials in free atoms

Based on the recently proposed Vosko-Wilk-Nusair interpolation formulae for the correlation energy density of the spin-polarized homogeneous electron liquid, a new parametrized form for the correlation potential for the self-consistent local-spin-density calculations of atoms, molecules and solids is proposed. The total energies and first ionization potentials for a few light atoms are calculated. The influence of the improved spin-polarization dependence on the calculated quantities is investigated, too. The calculated ionization potentials are in good agreement with observed values and are better (in average by 0.3 eV) than the values predicted by the hitherto most commonly used correlation potentials within the local spin density approximation.