Vibrational-state-selected ion--molecule reaction cross sections at thermal energies

Abstract

A method designed to measure relative ion—molecule reaction rates at thermal collision energies for selected reactant ion vibrational states is described. Relative reaction rates are determined for the three endothermic reactions: H2+ (υ)(He,H)HeH+, H2+ (υ)(Ne,H)NeH+, D2+(υ)(Ne, D)NeD+, and for the two exothermic reactions H2+ (υ)(H2, H)H3+, D2+(υ)(D2, D)D3+, whereby data are evaluated for υ = 0–8 for H2+ and for υ = 0–12 in the case of D2+. The results are analyzed in terms of a modified statistical model designed for reactions that go through a collision complex. It is found that all data can be satisfactorily described within this model.