Reactions between isotopically labeled N2+ and N2 for primary ion energies below 45 eV

Abstract

Apparent cross sections for electron transfer between N2+15 and 14N2 and for the reactions (1) N2+ + N2 → N3+ + N, and (2) N2+ + N2 → N+ + N + N2 have been measured, with the primary ion and target molecules isotopically labeled. The laboratory kinetic energies E of N2+ are between 3 and 45 eV. The effect of excited states of N2+ is studied. Reactions (1) and (2) proceed both by processes which involve dissociation of the primary N2+ and by processes which involve dissociation of the target N2. Processes which involve dissociation of the primary ion are favored, and even more so when the primary N2+ is excited by ∼8.5 eV to unidentified, long-lived states. The isotopic composition of the reactants influences Reactions (1) and (2) significantly; these isotopic effects may be caused by kinematic phenomena. It is suggested that Reaction (1) proceeds via stripping processes which convert most of the reactants' kinetic energy into internal energy of the N3+ and/or N products. Reaction (2) may proceed either through the formation and disintegration of excited N3+ or through some unidentified mechanism. A survey of the available information on N2+ suggests that the production and lifetimes of the various states of N2+ may now be well-enough known to permit detailed comparisons between theory and experiment.