Quasimolecular or kinematical broadening of autoionization electron spectra from Li+/He collisions? a coincidence study

We have measured energy- and angular distributions of autoionization electrons from Li⁺/He collisions in coincidence with the scattered Li⁺ projectiles. The coincident energy spectra do not exhibit the broad structures that are observed in the non coincident spectra and which in the past were attributed to quasimolecular autoionization of the (LiHe)⁺ system. We show that these broad structures are caused by kinematical shifts of electron spectra from pure atomic autoionization following different scattering events. With an exploitation of published inelastic differential scattering cross sections and with the assumption that the angular electron distribution with respect to the asymptotic internuclear line is nearly independent of the scattering angle we are able to reproduce the non coincident electron spectra satisfactorily.