Experimental evidence for vacancy sharing between L subshells in very asymmetric ion-atom collisions

Abstract

The impact parameter dependence of L-subshell ionisation probabilities I(Li(b)) has been measured for 0.9 MeV u-1 He on Pt (Zua=80), Ne on Pt (Zua=88) and Ne on Yb (Zua=80), and for 6 MeV p on Au. For the collision system 0.9 MeV u-1 (I(b)<10-3) the authors observed the crossing of I(LI) and ILIII) at a very low value of the impact parameter, in good agreement with first-order perturbation theory; this crossing is due to relativistic effects in the electronic wavefunctions. For increasing perturbation (I(b) to 10-2), however, the b dependence of measured L-subshell ionisation probabilities I(Li(b)) differs strongly from the predicted values. These deviations can be explained by vacancy sharing mechanisms between the L subshells during the collision process.