Excitation of the 1s2- and 1s4-levels of neon and argon by He+-impact at energies between 100 keV and 1000 keV

The excitation of the 1s2- and 1s4-levels of neon and argon by He+-impact has been studied in the energy range of 100 keV to 1000 keV. The total emission cross sections for the 1s2 levels show pronounced maxima at about 350 keV impact energy, whereas the cross sections for the 1s4 levels increase with decreasing energy.