Electron transfer in collisions of doubly charged rare gas ions and rare gas atoms for primary ion energies below 100 eV

Cross sections for the production of Kr⁺, Ne⁺, and Kr⁺⁺ in collisions of Kr⁺⁺ with Ne and of Ne⁺⁺ with Kr have measured for primary ion energies E between 0.5 and 100 eV. For $\text{E≳ 10\hspace{0.17em}}\mathrm{eV}$ , the cross sections all vary rather slowly and are between 1 and 8 Ų. As E is decreased below 5–10 eV, the cross sections all increase. The cross section σ_a measured for Kr⁺⁺ +Ne→Kr⁺ + ⋯ is expected to be a reasonably accurate representation of the cross section for Kr⁺⁺ +Ne→Kr⁺ +Ne⁺; σ_a has been compared with three theoretical results for this reaction, but the theoretical and experimental results do not agree very well. The implications of the discrepancies between theory and experiment are discussed. σ_a is in good agreement with an earlier measurement of Kr⁺⁺ +Ne → Kr⁺ + ⋯ at higher E. The efficiency with which product ions are collected by the present apparatus is discussed.