Total cross sections for low energy collisions of H3+ with molecular hydrogen and rare gases

Abstract

Measurements of total cross sections for collision induced dissociation (CID) and proton abstraction have been made for the reactants H3++H2, Ar, and He. The laboratory collision energies range from a few up to 400 eV and D3+ has been substituted to investigate possible isotope effects. The CID cross sections of H3+→H++H2 or H2++H maximize at a value of a few Å2. Proton abstraction is the dominant process for relative collision energies below 5 eV and is observed to lead to a highly excited H3+ product which often autodissociates. Dissociative charge transfer at higher collision energies is responsible for producing H2+ product ions. The role of internal energy contained within the H3+ primaries in previous experiments and the effects of internal energy on the cross section measurements presented here are also discussed.