Target Z dependence and additivity of cross sections for electron loss by 6-MeV/amu Xe18+ projectiles -: art. no. 022706

The dependence of electron loss by 6-MeV/amu Xe18+ on target atomic number was investigated by measuring single-collision cross sections for loss of one to eight electrons in targets of the noble gases He, Ne, Ar, Kr, and Xe. The total-electron-loss cross sections were found to increase linearly with target atomic number, but an abrupt slope change was observed to occur between Ne and Kr. Calculated total-loss cross sections obtained using the n-body classical trajectory Monte Carlo method were in good agreement with the measurements. The dependence of the individual cross sections on the number of electrons lost was reasonably well represented by a semiempirical fitting procedure utilizing the independent-electron approximation. Additional measurements performed with a variety of molecular targets provided a rigorous test of cross-section additivity. It was found that the additivity rule works well in this collision regime and that the molecular nature of the target has remarkably little influence on the cross sections.