Multiple ionization and capture in energetic ion-atom collisions: He atom targets

Abstract

A semiclassical model that follows the motion of all electrons in a target atom is developed for the application to collisions of multiply-charged ions (5 ≲ q ≲ 50) with rare-gas atoms at intermediate energies (500 keV/u ≲ E ≲ 5000 keV/u). S ionization and capture cross sections are calculated for He atom targets using classical trajectories based on Hamilton's equations of motion. Results from calculations and experiments indicate a high degree of transfer ionization in the electron capture component of the collisions. Experimental data were measured at high energies in order to quantify the transfer ionization component in electron capture. These data, and previous measurements, were used to develop a scaling rule applicable to He targets for wide ranges of incident ion charge and energy.