Validity of the isolated resonance picture for H-2 autoionizing states

The isolated resonance picture (IRP) is tested by comparing calculations on doubly excited autoionizing states of H-2 by using two different theoretical approaches: a recent implementation of the exterior complex scaling method and the standard Feshbach method with B-spline basis sets. These calculations demonstrate that the IRP can yield poor approximations to autoionization widths when doubly excited states approach the ionization threshold at large internuclear distances, R. In contrast, at small R where avoided crossings appear, the IRP produces accurate resonance parameters.