Near-resonant charge transfer in collisions of rare-gas ions with simple molecules within the energy range 4-45 keV

The ionization produced by Xe⁺, Kr⁺ and Ar⁺ ions during passage through thin targets of H₂, N₂, O₂ and CO has been investigated by the mass spectrometric analysis of the secondary ion products. Cross sections for the formation of particular secondary ions have been determined within the energy range 4-45 keV. The results show that, although fragmentation is always significant, non-dissociative processes generally account for over 70% of the molecular ionization. When accidental near-resonant charge-transfer processes are possible such processes are even more important. The behaviour of the non-dissociative cross sections is shown to be consistent with the simple adiabatic hypothesis.