Final Charge States of Ions Scattered to Large Angles by Single Collisions

Measurements of the charge states of ions following ion or atom excitation, have been used as probes of atomic structure since the early 1900´s. More recently, the investigation of the final charge states of heavy ions scattered from heavy atoms has led to the realization that much of the ionization results from the production and subsequent cascade filling of inner-shell vacancies. The development, by Fano and Lichten, of the molecular orbital model for heavy ion-atom collisions has made our present understanding of these collisions possible. Today charge state measurements are made not only because of their intrinsic interest, but because they shed light on the molecular dynamics of collisions over a wide range of collision energies. It is found that collisions from 100 ev to 100 Mev can have features in common, and that an effective way of testing the molecular orbital model over this wide range of energies is to measure charge states as a function of scattering angles for single collisions.