Cross sections for symmetric charge transfer reactions of NO+ in selected vibrational and translational energy states

Abstract

The cross sections for symmetric charge transfer reactions of NO+ in selected vibrational and translational energy states have been measured in a single chamber experiment using a combination of photoion–photoelectron coincidence and time of flight ion analysis. The ion vibrational states and translational energies investigated were v=0–5 and 1–60 eV, respectively. A test study of the Xe charge exchange reaction demonstrates the ability of this experiment to produce accurate absolute rates. In the symmetric charge transfer reaction of NO+(v), the influence of the ion vibrational state was found to be most predominant at low translational energies. The cross sections for the reactions of ions in the first three vibrational states tend to follow Franck–Condon factors, however at higher vibrational states additional reaction channels evidently compensate thus increasing the cross sections. The data are compared to recently reported theoretical cross sections using the multistate approximation. The theory overestimates the cross sections by a factor of approximately 2.0. Although the theory correctly predicts the relative rates of v=0, 1, and 2, it fails to account for the high cross sections of v=3 and 4 relative to those for the lower ion vibrational states.