Representation of the electronic continuum of with<b><i>B</i></b>-spline basis

Abstract

We present an integrable method with B-spline basis to describe the electronic continuum of two-electron diatomic molecules. The method is applied to obtain (i) energy positions and widths of the lowest doubly-excited states of the molecule, and (ii) photoionization cross sections of in the fixed-nuclei approximation. Our results are compared with existing theoretical and experimental works. We show the existence of avoided crossings between two series of doubly-excited states, and , converging to the ionization threshold of .