Applying electron propagator theory to electron affinities

Electron propagator theory is used to calculate vertical ionization energies of closed shell anions. Third order diagonal self-energies are calculated using the post-Hartree–Fock utility subroutines of GAUSSIAN 82. Higher order corrections are estimated using the outer valence approximation. The number of operations needed rises no faster than the number required for the limited two-electron integral transformation. Basis set augmentations are made until changes in the computational results are small. Adiabatic ionization energies are obtained via many body perturbation theory calculations on the neutral potential energy surface. Applications to BeH- and MgH- give results in excellent agreement with photodetachment experiments.