Single-electron capture and loss cross sections versus targetZfor 1 MeV/u oxygen ions incident on gases

In an ion-atom collision electron capture and loss depend, in general, on the beam energy, projectile charge state, and target Z. While most fundamental theories of capture and loss are formulated in terms of a single electron moving in the fields of the pertinent nuclei, various scaling laws have been developed to account for partially stripped ions and multielectron targets. The purpose of the present work is to systematically examine the dependence of capture and loss cross sections on target Z. Cross sections for single-electron capture and loss for 1 MeV/u oxygen ions passing through gas targets were measured as a function of target Z for incident projectile charge states of 5+, 6+, 7+, and 8+. The targets used were ${\mathrm{D}}_2$, He, Ne, Ar, and Kr. The electron-capture measurements are generally in reasonable agreement with existing theoretical and empirical scaling rules. The electron-loss cross sections differ appreciably from predictions of the plane-wave Born approximation, particularly for the heaviest targets studied.