To study the usefulness of second-order Moller-Plesset (MP2) correlation energies for ground states of closed-shell atoms (referred to as MP2/CA energies) in estimations of the total correlation energies of larger closed-shell atoms, we have considered atoms and ions containing from 10 to 86 electrons. First, it is demonstrated that for N-electron systems, 10≤N≤18, the MP2/CA energies provide very good approximations to the very accurate estimates of atomic correlation energies by Chakravorty and Davidson. Next, for systems with 10≤N≤54 comparisons are made with the semiempirical energies obtained when using the models by Charkravorty and Clementi as well as by Clementi and Corongiu. Finally, for atoms with 10≤N≤86 the MP2/CA energies are employed for comparison with DFT energies recently obtained by Andrae et al. The MP2/CA results have proven to provide reasonable estimates to the total correlation energies in all the cases considered.
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