From direct to resonant photo-double ionization

The concepts developed for direct photo-double ionization are deployed to analyse recent experimental data for indirect or resonant photo-double ionization of Ca in the region of the 3p-3d resonance given by Ross et al . As in the direct process the features in the triple differential cross sections can be understood in terms of selection rules, final-state electron correlation and interference effects. For most directions of the two-electron momenta strong destructive interference between various partial waves is found.