Benchmark calculations with correlated molecular wave functions. X. Comparison with “exact” MP2 calculations on Ne, HF, H2O, and N2

摘要: The convergence of the MP2 valence correlation energy and pair energies for consistent basis sets has been investigated. Ne, HF, H2O, N2 were studied. For all these molecules, accurate are available from recent MP2-R12 calculations W. Klopper [J. Chem. Phys. 102, 6168 (1995)]. magnitudes calculated found to increase systematically with increasing set size, cc-pV6Z yielding 97.4%–98.3% energy. A detailed analysis results Ne reveals that error due truncation radial functions in is comparable neglect higher angular momentum functions. Procedures extrapolating complete limit have also