LOCAL AND NONLOCAL RELATIVISTIC EXCHANGE-CORRELATION ENERGY FUNCTIONALS - COMPARISON TO RELATIVISTIC OPTIMIZED-POTENTIAL-MODEL RESULTS

Relativistic corrections to the exchange-correlation energy functional of density functional theory are examined within the no-sea approximation to the full relativistic Kohn-Sham equations. We apply the relativistic optimized-potential model to spherical atoms in order to establish a comparative standard in the longitudinal exchange-only limit and use the results for an analysis of the corresponding relativistic local- and weighted-density approximations. In addition, we investigate transverse exchange and correlation contributions. A local-density approximation for the correlation energy functional is constructed from the relativistic high-density and the nonrelativistic limits and analyzed by comparison with quantum chemical data.