Dynamics of dissociative recombination of molecular ions: Three-body breakup of triatomic di-hydrides

An electron, recombining with a molecular ion, deposits the negative of the ionization potential into the system and leads to dissociation into atomic and/or molecular fragments (dissociative recombination (DR)). Recent studi es using heavy-ion storage rings have done much to elucidate the process. R elative collision energies as low as similar to1 meV are obtained, and info rmation has been gained on total cross sections (rates), fragment branching fractions, and atomic states in DR of diatomic molecules. Tri-atomic di-hy drides (H-3(+), CH2+, NH2+, OH2+) show a propensity for dissociation into t hree fragments. To study the dynamics of this process, a new method has bee n used to obtain atomic excitation levels, distribution of energy, and angu lar distribution of the fragments. The case study of H2O+ has been complete d and is discussed.