Charge transfer and ionization of lithium by protons and helium ions.

Abstract

Proton and helium-ion impact on atomic lithium is studied for impact energies ranging from 15 to 200 keV. By observing the final lithium charge states, cross sections for pure single electron capture from lithium as well as for single capture plus ionization are presented. Cross sections for double electron capture by ${\mathrm{He}}^{2+}$ projectiles are also measured and the decrease in the double-capture cross section below 20 keV/amu is confirmed. Cross sections for ionization of lithium by these same projectiles are also presented and compared with theoretical calculations.