Scaling in second-order electron correlation calculations using systematic sequences of even-tempered basis sets

摘要: Improved results can often be obtained from second-order Rayleigh-Schrodinger perturbation calculations of electron correlation energies using large basis sets by introducing a scaling factor in the zero-order Hamiltonian. The parameter may determined full third-order smaller set. This procedure applied systematic fashion employing sequence even-tempered sets. Calculations illustrating this approach for beryllium atom and neon are presented. is also employed conjunction with universal functions. Correlation energy — Mang-body theory.