Delayed-Coincidence Study ofO+-Xe Collisions at 50-210 keV

Delayed-coincidence techniques have provided measurements of $\overline{Q}\left(r_0\right)$ for ${\mathrm{O}}^{+}$ -Xe collisions in the energy range 50-210 keV; here $r_0$ represents the distance of closest approach of the colliding particles, and $\overline{Q}$ is the average energy transferred to inelastic processes. At fixed $r_0$ the $\overline{Q}$ values increase with bombarding energy. The $\overline{Q}$ values generally increase as $r_0$ decreases although they remain constant over some regions of $r_0$ within the range (0.05-0.25 Å) covered by the experiment. The $r_0$ regions in which $\overline{Q}$ increases appear to be correlated with regions in which the differential cross sections for beam-particle scattering fail to vary according to the predictions of the exponentially screened Coulomb potential. Simple interpretations of the data attribute these results to the effects of electronic shell interpenetrations during the collisions. Supplementing the $\overline{Q}$ and cross-section data are determinations of average ionic charge states after collision and calculations of inelastic energy-loss cross sections deduced from the $\overline{Q}$ results.