Hydrogen migration in triply charged acetylene

J Chem Phys. 2022 Apr 14;156(14):141101. doi: 10.1063/5.0086427.

Abstract

We report on the direct experimental evidence of hydrogen migration in triply charged acetylene. The roaming hydrogen atom in a triply charged molecular ion is counter intuitive. The three body breakup channel C2H2 3+→H++C++CH+ is studied using the technique of recoil ion momentum spectroscopy. The triply charged ion was generated in collisions of the neutral parent with a slow highly charged Xe9+ ion. Three different dissociation pathways have been identified and separated, namely, concerted breakup in an acetylene configuration, concerted breakup in a vinylidene configuration, and sequential breakup via a [C2H]2+ intermediate, and the branching ratio for all three pathways are determined.