Inelastic collisions of 2-800-eVHe+andHe2+with Mg and Zn atoms

Inelastic processes leading to excited-state formation have been studied by spectral analysis of collision-produced uv-visible-near-ir radiation for (2-800 eV) ${\mathrm{He}}^{+}$ and ${\mathrm{He}}_2^{+}$ collisions with Mg and Zn atoms. Although observation of MgII radiation must result from exothermic charge transfer in the ${\mathrm{He}}^{+}$-Mg system, the emission cross sections for the two observed MgII lines exhibit threshold behavior; it is suggested that production of ground-state MgIII dominates at low energy. ${\mathrm{He}}_2^{+}$-Mg collisions yield two prominent MgII lines, the emission cross sections for which are relatively large at low energy and decrease rapidly with increasing kinetic energy. ${\mathrm{He}}^{+}$-Zn collisions produce rich spectra of ZnII lines at all energies and HeI lines at elevated energies. In contrast, ${\mathrm{He}}_2^{+}$-Zn collisions yield only a few lines with large cross sections at low energy.