L3-subshell alignment in gold following low-velocity proton and He+impact ionisation

Abstract

By measuring the angular distribution of the Ll/Lgamma intensity ratio of gold following proton (E=0.6-1.5 MeV) and He+ (E/M=0.2-1.1 MeV amu-1) impact ionisation, the A2 alignment parameter of the L3 subshell has been determined. In contrast to the monotonic behaviour of A2 predicted by the PWBA at low projectile velocities, the authors' experimental data for He+ impact exhibit a minimum at E/M approximately=0.4 MeV amu-1 which can be explained by the deflection of the projectile in the Coulomb field of the target nucleus.