Theoretical study of the detachment process in the zero-range potential approximation. H--He collisions

A theoretical study of the detachment process in H--He collisions is presented for the 1-103 eV collision energy range. The outer electron of the colliding system is described in the zero-range potential approximation, the relevant parameters of which are extracted from an ab initio calculation of the (HHe)- molecular ion. This enables an exact treatment of the bound-state-continuum transitions induced by the nuclear motion. A very efficient approximation is also proposed to solve the collision problem. A detailed picture of the final state of the system is thus obtained (differential cross sections, total cross sections, spectra of ejected electrons, isotope effect) and compared with experimental data when available. (author)