One-step double autoionization into the double-photoionization continuum

We have determined the Fano parameters and oscillator strengths of the trip ly photoexcited Li 2s(2)2p P-2(0) autoionizing resonance in the Li+ and Li2 + partial photoion yields. Using monochromatized photons we observed an asy mmetric resonance profile not only in the Lit but also in the Li2+ partial cross section. The interaction between the triply excited state and the dou ble-photoionization continuum takes place via a onestep double autoionizati on, since a two-step autoionization of the discrete state is energetically not possible. Our theoretical calculations using an R-matrix method for bot h the Li+ and Li2+ partial cross sections show resonance profiles in good a greement with experimental result.