Dissociative photoionization of H2 and D2 by (30-37)-eV photons via 1Πu states

We present a theoretical study of dissociative photoionization of H-2 and D-2 via (IIu)-I-1 states, in the photon energy range 30-37 eV where several ionization and dissociation channels are open. The theory includes coherently competition between the different dissociation and ionization channels, and makes use of B-spline functions to represent both the electronic and nuclear motions. Our results agree fairly well with recent experiments, and show that the various peaks observed in the spectra are due to the lowest Q(2) (IIu)-I-1 doubly excited state, which decays following both a direct and a multistep mechanism. The differences between H-2 and D-2, results can be explained in terms of calculated Franck-Condon factors and autoionization probabilities. [S1050-2947(99)10109-4].