Reactions of N + and N 2+ with several cyclic molecules studied using a selected ion flow tube

Abstract

A selected ion flow tube, SIFT, has been used to investigate the reactions of N + and N 2 + with four cyclic molecules (pyrrole, pyrrolidine, benzene, and cyclohexane) at 298 K. These species are of particular interest to the chemistry of both Titan's ionosphere and of interstellar molecular clouds. Rate coefficients and product distributions have been determined to provide kinetic data needed for accurate models of these media and establish chemical routes. The majority of reactions proceed at the gas kinetic rate; only pyrrolidine reacts slower. The reactions result mainly in dissociative charge transfer, except the reaction of benzene with N +, in which the major product is non-dissociative charge transfer. Comparisons are made between each neutral with the two reactant ions (N + and N 2 +) of differing recombination energies and also between each reactant ion with neutrals differing in ionization energy and aromaticity. Fragmentation channels are discussed and compared with electron impact ionization.