Correlation energy differences have been evaluated using an empirical polarization potential for the two-, three-, and four-electron atom series. In contrast to local-density approximations the Z dependency of the correlation energies has been well reproduced. Moreover, the quantitative agreement with experimental values is surprisingly good. Deviations are smaller than 0.01 hartree.

• Received 10 November 1987

DOI:https://doi.org/10.1103/PhysRevA.38.483