Electron transfer reactions in collisions of low energy Neq+ (q = 3–5) ions with CO2 and H2O molecules

Collision spectroscopy has been used to measure energy spectra and absolute total cross sections for single- and double-electron transfer reactions in low-energy collisions of Neq+ (q = 3–5) ions with CO2 and H2O at impact energies between 15 and 500 q eV, where q is the projectile charge state. The energy spectra show that only a few final states were selectively populated depending on the charge state of the projectile. In all collision systems studied here, the dominant reaction channels are due to non-dissociative single-electron transfer into excited states of the projectile product. For collisions of Ne3+ and Ne4+ ions with CO2 and H2O reaction channels correlated with transfer excitation were also observed. The energy dependence of cross sections for single- and double-electron transfer are also measured and found to slowly increase with increasing impact energies. The measured cross sections for single-electron transfer are also compared with theoretical calculations of the Multichannel Landau–Zener (MCLZ) model and the classical over the barrier (COB) model. The projectile charge state dependence of the cross section ratio of double to single-electron transfer increases with increasing the charge state in disagreement with the calculations based on an extension of the classical over-the-barrier model to multi-electron transfer, which predicts that the ratio is independent of the charge state.

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