Energy density analysis for second-order Møller-Plesset perturbation theory and coupled-cluster theory with singles and doubles: application to C2H4--CH4 complexes.
Grid-based energy density analysis (EDA), in which numerical integration is performed for two-electron integrals by the pseudospectral method (Imamura et al., J. Chem. Phys. 2007, 126, 034103), is extended to correlated methods: second-order Møller-Plesset (MP2) perturbation and coupled-cluster singles and doubles (CCSD). Using EDA for MP2 and CCSD, we estimate atomic correlation energy differences and correlation energy density difference maps for C(2)H(4)--CH(4) complexes. The analyses confirm that polarization and diffuse functions essentially contribute to the descriptions of weak interaction around the nuclei and in the area between C(2)H(4) and CH(4), respectively.
Imamura
Yutaka
Y
Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Tokyo 169-8555, Japan.
Nakai
Hiromi
H