Simple method for constructing accurate atomic Kohn-Sham potentials

Recently, a great deal of attention has been devoted to the near-exact Kohn -Sham (KS) atomic potentials, mainly obtained from quantum Monte Carlo (QMC ) calculations for a few significant test cases; We show that the potential of the highest occupied orbital in the self-interaction corrected local-de nsity approximation (SIC LDA) approach provides an excellent approximation for the QMC potentials, far better than the commonly used ones. Moreover, n ear-exact KS potentials of the same quality as the QMC ones can be obtained from the SIC-LDA potentials of the highest occupied and lowest empty orbit als, by a simple two-parameter fitting procedure to reproduce the experimen tal values of the ionization and first excitation energies. This has been d emonstrated by a quantum-defect analysis of the empty states of Ne and Be a toms, for which QMC potentials are available to us. The introduced method i s used to construct a near-exact KS potential for Ar. [S1050-2947(99)00910- 5].