Doubly excited states of beryllium and magnesium

The noniterative eigenchannel R-matrix method is used to study the properties of the valence electrons in Be and Mg ${}_{}{}^1{}_{}{}^{}\mathrm{P}_{}^{\mathrm{o}}{}_{}{}^{}$ states. Our results detail the evolution of electron correlations as a function of energy. Besides obtaining an improved quantitative description of doubly excited states in these atoms, we verify the conclusion of an earlier hyperspherical-coordinate study that the wave functions are exact analogs of the sp+ and sp- states of helium and ${\mathrm{H}}^{\mathrm{-}}$. .AE