Near thermal energy charge transfer reactions of rare gas ions with diatomic and simple polyatomic molecules: The importance of Franck-Condon factors and energy resonance on the magnitude of the rate constants

Abstract

Charge transfer rate constants for reactions of He+, Ne+, Ar+, Kr+, and Xe+ with N2, O2, CO, NO, CO2, N2O, and CH4 were measured using an ion cyclotron resonance spectrometer. The absolute values of the rate constants were within the upper limit predicted from the Gioumousis-Stevenson orbiting theory for ion-molecule reactions. The magnitudes for the charge transfer rate constants are discussed with respect to (1) the availability of an energy level of the molecular ion resonant with the recombination energy of the rare gas ion, and (2) the value of the Franck-Condon factor connecting this energy level of the molecular ion with the molecular neutral.