Differential cross sections for elastic and inelastic scattering of 15-100-keV Li+ by He

Sets of energy-loss spectra for ${\mathrm{Li}}^{+}$ incident on He that were taken at a series of scattering angles were used to calculate differential cross sections. Differential cross sections are given for elastic scattering and for excitation of the He ($n=2$) states. The differential cross section is also given for excitation of states corresponding to a 60-eV energy loss. These inelastic differential cross sections exhibit maxima at scattering angles greater than zero. The velocity dependence of the cross sections can be compensated by displaying the elastic data in $\ensuremath{\rho}$-vs-$\ensuremath{\tau}$ plots and the inelastic data in $\ensuremath{\rho}$-vs-${E}^{\frac{3}{2}}\ensuremath{\theta}$ plots. When displayed in terms of these variables, the data are strikingly similar to those reported for ${\mathrm{Li}}^{+}$ + He collisions at much lower impact energies.