Behaviors of excitation cross sections in the intermediate velocity regime on ion-atom collisions

We studied the behaviors of excitation cross sections and electron capture cross sections as functions of collision velocity using previous data of various collision systems. The structures peculiar to the intermediate velocity regime were recognized on the excitation cross sections. Close correlation of the excitation cross section to the electron capture cross section and a relaxation time longer than that for the electron capture press characterize the excitation process in the intermediate velocity regime. A model consisting of a two-step electron transfer process well explains the characteristics of the excitation cross sections in the intermediate velocity regime. (author)