title: General-Order Many-Body Green's Function Method.
abstract: Electron binding energies are evaluated as differences in total energy between the N- and (N ± 1)-electron systems calculated by the nth-order Møller-Plesset perturbation (MPn) theory using the same set of orbitals. The MPn energies up to n = 30 are, in turn, obtained by the determinant-based method of Knowles et al. (Chem. Phys. Lett. 1985, 113, 8-12). The zeroth- through third-order electron binding energies thus determined agree with those obtained by solving the Dyson equation in the diagonal and frequency-independent approximations of the self-energy. However, as n → ∞, they converge at the exact basis-set solutions from the Dyson equation with the exact self-energy, which is nondiagonal and frequency-dependent. This suggests that the MPn energy differences define an alternative diagrammatic expansion of Koopmans-like electron binding energies, which takes into account the perturbation corrections from the off-diagonal elements and frequency dependence of the irreducible self-energy. Our analysis shows that these corrections are included as semireducible and linked-disconnected diagrams, respectively, which are also found in a perturbation expansion of the electron binding energies of the equation-of-motion coupled-cluster methods. The rate of convergence of the electron binding energies with respect to n and its acceleration by Padé approximants are also discussed.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors.forename: So
authors.initials: S
authors.lastname: Hirata
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hermes
authors.affiliation: Department of Chemistry, University of Utah , Salt Lake City, Utah 84112, United States.
authors.forename: Jack
authors.initials: J
authors.lastname: Simons
authors.affiliation: Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849-5312, United States.
authors.forename: J V
authors.initials: JV
authors.lastname: Ortiz