Green's function calculations using non‐Hartree–Fock orbitals

Abstract

AbstractThe single‐particle Green's function is used to generate a new zero‐order Hamiltonian. The idea to generate a new zero order from the previous zero order by incorporating perturbative corrections up to certain order is attractive since it allows an iterative procedure to repeatedly improve the results by decreasing the perturbation. In particular, in those cases where the Hartree–Fock Hamiltonian is not a good approximation to the full Hamiltonian and where perturbation theory usually does not produce sufficiently accurate results, one might hope that such a repetitive procedure ultimately yields an improved zero order and accurate perturbative corrections from this newly generated zero order. Two such approaches are investigated: first, one in which the ω‐independent part of the self‐energy is fully incorporated in the zero order and, second, one in which the correlation energy is incorporated in a one‐electron potential in an average way. Numerical calculations are reported.