Possible rearrangement processes in L-shell ionisation of atoms by heavy ions

The authors investigate the possibility of collision-induced transitions of a vacancy between the L subshells of atoms, when the vacancy is created by direct ionisation at heavy-ion impact. A simple model with a two-step mechanism for the production and rearrangement of a vacancy is presented. The success of this model indicates that intra-shell excitations (de-excitations) during the collision are probably responsible for the previously observed large discrepancies between the theory and experiment in the L-shell ionisation of gold by carbon, nitrogen and oxygen ions.