The effects of collision energy and ion vibrational excitation on proton and charge transfer in H2++N2, CO, O2

Abstract

The effects of vibrational excitation of reagent ions and collision energy on the proton and charge transfer reactions of H₂⁺ and D₂⁺ with N₂, CO, and O₂ have been investigated using a method combining photoionization and a radio frequency guided ion technique. For proton transfer the H₂⁺+N₂ results are quite similar to the H₂⁺+Ar system; proton and charge transfer channels are closely coupled for kinetic energies above 3 eV. In contrast, for H₂⁺+CO, the vibrational dependence of proton transfer is quite weak. For the H₂⁺+O₂ case, evidence is seen for direct competition between the charge and proton transfer process. A simple model for charge transfer is used to assess the importance of energy resonance and Franck–Condon effects. In these simple molecular systems, the energy defect is found to be most important to charge exchange, although Franck–Condon factors play a substantial role.