Second-order propagator calculation of a doublet <i>P</i> Mg shape resonance

Abstract

We report several calculations on the doublet P shape resonance in the Mg atom by use of a second-order, complex-scaled electron propagator. The results agree with experiment within experimental error, and these are attained within quite small basis sets. Rules for construction of the complex scaled self-energy are given. The diagrammatic expansion corresponds to that for a system in a scaled external potential.