Self-Consistent-Field Theory for One-Positron Many-Electron Systems

A theory for the structure of one-positron many-electron atoms and molecules in bound states is presented. The purpose of the theory is to permit the accurate calculation of positron lifetimes, angular correlation for two-photon annihilation, and accurate positron binding energies, but not necessarily quantities which depend upon purely electronic correlation. We therefore use a modified orbital approximation for the electrons, the modification consisting of the introduction of explicit electron-positron correlation into each electronic orbital. The kinetic energies of the electrons and positron are treated on the same footing, and the Born-Oppenheimer approximation is applied to the nuclei. No spin-dependent or relativistic terms are included in the Hamiltonian. In this paper we treat only those systems for which the electrons constitute a closed shell, and we do not consider the spatial symmetry of the atom or molecule.