HYDROGEN-ATOM TRANSFER-REACTIONS OF N-2+ WITH H-2, HD, AND D2 FROM THERMAL TO 10 EV CENTER OF MASS

Reactions of N2+ ions with H-2, HD, and D2 are studied under single-collision conditions in a guided-ion beam mass spectrometer over a much broader range of interaction energies than in any previous study, including the low energy region of thermal to 0.1 eV. Reactant ions are formed in a flow tube source to ensure thermalization. Possible reaction mechanism are discussed, and the present results are compared to previous measurements. We find that the reaction proceeds at the rate predicted by the classical ion-molecule capture collision theory at thermal energy, but exceeds this prediction at energies above 0.1 eV. This behavior is discussed and attributed to details of the interaction between the N2+ + H-2 surface and the N2 + H-2+ surface along which the hydrogen atom transfer reaction proceeds. Intramolecular isotope effects and product ion dissociation behavior suggest that the reaction occurs via a direct mechanism with no long-lived intermediate at elevated energies.