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 studies using heavy-ion storage rings have done much to elucidate the process. Relative collision energies as low as ∼1 meV are obtained, and information has been gained on total cross sections (rates), fragment branching fractions, and atomic states in DR of diatomic molecules. Tri-atomic di-hydrides (H3 +, CH2 +, NH2 +, OH2 +) show a propensity for dissociation into three fragments. To study the dynamics of this process, a new method has been used to obtain atomic excitation levels, distribution of energy, and angular distribution of the fragments. The case study of H2O+ has been completed and is discussed.