Charge States of Ne and Ar Ions Scattered to Large Angles by Ar Atoms for Collision Energies up to 3.0 MeV

Abstract

The impact parameter dependence of inner-shell excitations in single heavy ion-atom collisions can be determined from the final charge state of the scattered ion as a function of the scattering angle and collision energy. In our work, the final charge states for 0.15 MeV to 1.5 MeV Ne⁺ ion-projectiles scattered through angles from 1–20° by Ar atoms have been measured. Similar measurements for the Ar⁺-Ar system from 0.5 to 1.0 MeV, and for the Ar⁺⁺-Ar system at 3.0 MeV, were made. When the average charge state, m̄, of the scattered ions is plotted as a function of the product E_oθ of the incident ion-energy and the scattering angle for these systems, m̄ is observed to increase by one or two units for specific values of E_oθ. Because E_oθ is closely related to R_o, the distance of closest approach for the collision, these increases are indicative of inner-shell vacancies being produced through molecular orbital interaction.