Sj. Chakravorty et Er. Davidson, REFINEMENT OF THE ASYMPTOTIC Z-EXPANSION FOR THE GROUND-STATE CORRELATION ENERGIES OF ATOMIC IONS, Journal of physical chemistry, 100(15), 1996, pp. 6167-6172
Davidson and co-workers (Phys. Rev. A 1991, 44, 7071; 1993, 47, 3649)
have estimated the nonrelativistic correlation energies and relativist
ic corrections to ionization potentials for atomic ions with up to 18
electrons. However, due to the lack of theoretical values for the high
-Z limits and lack of more accurate compilations of experimental ioniz
ation potentials, the analysis for 11-18 electrons required further in
vestigation. In this work, we have accurately determined the exact hig
h-Z limit employing degenerate second order perturbation theory for th
e correlation contribution to the energies of atomic ions with 3-18 el
ectrons. We have also incorporated the experimental compilation of the
electron affinity data of Hotop and Lineberger for the low-Z limit. T
his high-Z limit is compared with the results of the LYP correlation e
nergy functional. The LYP correlation functional is also compared with
the correlation energy of electrons in an external harmonic potential
of infinite force constant.