Application of accurate MP2 energies for closed-shell atoms in examinations of density functionals for 3d10 electron ions

Arguments are presented that accurate second-order Moller-Plesset (MP2) energies, evaluated in calculations involving extensive radial and angular basis sets, followed by careful angular extrapolations (referred to as MP2/CA energies), provide reliable approximations to the correlation energies for the ground states of closed-shell atomic systems. MP2/CA energies are calculated for the members of the Cu+ isoelectronic series (Cu+, Zn2+, Ge4+, and Kr8+), which belong to the simplest atomic system containing the 3d(10) configuration. The most accurate ab initio correlation energies for a 28-electron isoelectronic series are reported. To exemplify the applicability of the total nonrelativistic energies, obtained as a sum of these energies and accurate Hartree-Fock energies, in examinations of density functionals, density functional theory energies are calculated for various functionals and basis sets and compared with their MP2/CA counterparts. An evaluation of the performance of these functionals is presented. The impact of the limited basis set size on the energy results is estimated. (C) 2004 Wiley Periodicals, Inc.