Asymptotic behavior of MP2 correlation energies for closed-shell atoms

The asymptotic behavior of the second-order energy of the Moller-Plesset perturbation theory, especially adapted to take advantage of the closed-shell atomic structure (MP2/CA), is studied. Special attention is paid to problems related to the derivation of formulae for the asymptotic expansion coefficients (AECs) for two-particle partial-wave expansions in powers of (l + 1/2)(-1). These formulae providing a direct relationship between the Hartree-Fock orbitals defining the zero-order problem and the asymptotic structure of various constituents of the second-order energy are of interest for complete-basis-set limit studies of the correlation energies in general many-electron systems. Two ways of employing the easily available theoretical AECs in studies of correlation energies are indicated. The results obtained for the Zn2+ ion are encouraging.