Photoionization of the Be isoelectronic sequence from the ground and the ¹S bound excited states

Theoretical photoionization spectra below the 2p threshold of the Be isoelectronic sequence from the ground and a few selected ¹S bound excited states are calculated using a B-spline-based configuration-interaction approach. The resonant structures of the doubly excited autoionization series following photoionization from different initial states are analyzed in detail in terms of various initial- and final-state multielectron interactions. In addition, our calculation has shown that the resonant widths vary smoothly as functions of the effective principal quantum number ν along the autoionization series and approach approximately an expected ν^-3 dependence as ν increases.