Excitation of the He(2S1)and2P1) States by 15-100-keVLi+Bombardment

Excitation of the $\mathrm{He}\left(2\mathrm{}{}_{}{}^1{}_{}{}^{}S\right)$ state by 15-100-keV ${\mathrm{Li}}^{+}$ bombardment has been studied as a function of the angular scattering of ${\mathrm{Li}}^{+}$. The ratio of $\mathrm{He}\left(2\mathrm{}{}_{}{}^1{}_{}{}^{}S\right)$ to $\mathrm{He}\left(2\mathrm{}{}_{}{}^1{}_{}{}^{}P\right)$ excitations is about 0.6 and appears to be independent of both ${\mathrm{Li}}^{+}$ energy and scattering angle. Excitation of the $\mathrm{He}\left(2\mathrm{}{}_{}{}^1{}_{}{}^{}S\right)$ state indicates an inability of correlation diagrams based on the electron promotion model to predict all of the excitation products for ${\mathrm{Li}}^{+}$ + He collisions in this energy range.