Excitation mechanism in collisions of hydrogen atoms with highly charged ions

Abstract

The authors have calculated, with a finite difference method, a numerical solution of the time-dependent Schrodinger equation in the impact parameter theory of ion-atom collisions. They present results for excitation of the n=2 level of atomic hydrogen by fully stripped ions with charge up to 30. Though the total excitation cross section saturates for large projectile charges, no similar behaviour is observed in the impact-parameter-dependent probabilities. The latter show a maximum that shifts toward larger impact parameters and decreases in magnitude as the projectile charge increases. Thus the authors prove the validity of the dipolar approximation and hence justify the previously observed scaling rules. The symmetric eikonal approximation gives close agreement with the results of the numerical solution.