Third-order many-body perturbation theory calculations for the beryllium and magnesium isoelectronic sequences
Third-order many-body perturbation theory calculations for the beryllium and magnesium isoelectronic sequences
Third-order relativistic many-body perturbation theory (MBPT) is applied to obtain energies of ions with two valence electrons in the no virtual-pair approximation (NVPA). A total of 302 third-order Goldstone diagrams are organized into 12 one-body and 23 two-body terms. Only third-order two-body terms and diagrams are presented in this paper, …