KOHN-SHAM CALCULATIONS WITH SELF-INTERACTION-CORRECTED LOCAL-SPIN-DENSITY EXCHANGE-CORRELATION ENERGY FUNCTIONAL FOR ATOMIC SYSTEMS

We have investigated the accuracy of the local-spin-density approximat ion with orbital-density-dependent self-interaction correction (LSDSIC ) as proposed by Perdew and Zunger within a Kohn-Sham approach in whic h electrons with a given spin projection all move in a single optimize d effective potential (OEP). We have also studied the accuracy of the Krieger-Li-Iafrate (KLI) approximation to the OEP for the same energy functional in order to assess its applicability to systems in which th e integral equation for the OEP cannot be reduced to a one-dimensional problem, e.g., molecules. Self-consistent Kohn-Sham LSDSIC calculatio ns have been performed for atoms with atomic number Z=1-20 in the exch ange-only case for the total energy, the highest-occupied orbital ener gy epsilon(m), and the expectation value of r(2). In addition, the str ucture of the resulting exchange potential is examined and compared wi th the exact exchange-only density-functional theory (OEP method with Hartree-Fock exchange-energy functional) results. Furthermore, we disp lay epsilon(m), the ionization potential I, and the electron affinity A when both exchange and correlation energy effects are included. Fina lly, we also consider the results of evaluating the LSDSIC energy func tional by employing the exact (in the central-held approximation) sing le particle orbitals as proposed by Harrison. We find that the LSDSIC energy functional generally leads to calculated values that are superi or to those provided by the LSD approximation and that the KLI approxi mation yields results in excellent agreement with the corresponding ex act OEP results for this energy functional. In particular, quantities strongly related to the behavior of the valence electrons are nearly i dentical in both the OEP and KLI calculations, i.e., the difference be tween the [r(2)] and epsilon(m), is less than 0.2% on average, while t he difference between the calculated I is less than 0.2 millihartree o n average with the corresponding difference of only 0.1 millihartree f or A.