Delayed-Coincidence Study ofO++ Ne Collisions at 50-200 keV

Abstract

Delayed-coincidence techniques have provided measurements of the distributions in values of $Q$, the energy transferred to inelastic processes, during ${\mathrm{O}}^{+}$ + Ne collisions at 50-200 keV. The average values $\overline{Q}$ of the $Q$ distributions remain almost constant as a function of ${r}_{0}$, the distance of closest approach of the colliding particles. For fixed ${r}_{0}$, the $\overline{Q}$ values vary slowly with bombarding energy and lie, for example, approximately 40 eV higher at 100 keV than at 50 keV. The flatness of the $\overline{Q}({r}_{0})$ functions is reflected in a similar independence of ${r}_{0}$ found in measurements of the average charges of the particles after collision. These results indicate that the collisions produce excitations only among $L$-shell electrons. However, some data describing the widths of certain $Q$ distributions indicate that $K$-shell excitations may occur infrequently among collisions that produce ${\mathrm{O}}^{+4}$ ions. Supplementing the data for inelastic energy transfers are determinations of average ionic charge states after collision, measurements of angular distributions of scattering cross sections, and calculations of inelastic energy-loss cross sections deduced from the $\overline{Q}$ data.