Dissociative Photoionization of He ••• Li2: A Theoretical Study

Dissociative photoionization of the He center dot center dot center dot Li-2 van der Waals complex to the ground electronic state of the He center dot center dot center dot Li-2(+) ion is investigated theoretically. The photoionization cross section is computed using existing interaction potentials. Resonances are found on top of a structured continuum. They are assigned to vibrational predissociation of the ion by comparison with Fermi Golden Rule calculations. Because of the differences in potential energy surfaces between the neutral and ionic complexes, only the resonances corresponding to quasibound states with the highest excitation in the van. der Waals modes are visible. The other quasi bound states obtained in the Fermi Golden Rule calculations can give information on vibrational energy relaxation rates in other collisional processes involving the lithium dimer ion and a helium atom.