Thermochemistry of uranium sulfide cations: guided ion beam and theoretical studies of reactions of U+ and US+ with CS2 and collision-induced dissociation of US+

Reactions of atomic uranium cations with carbon disulfide form US+ in an efficient exothermic reaction and UCS+ in an inefficient endothermic process. The subsequent reaction of US+ with CS2 forms US2+ in an endothermic process having a low energy threshold. At much higher energies, UCS2+ and UCS+ are also formed. Collision-induced dissociation of US+ with Xe yields U+ + S exclusively in an endothermic reaction. Analysis of the kinetic energy dependent cross sections of the endothermic processes yields the 0 K bond dissociation energies of 5.73 +/- 0.15 eV for U+ - S, 3.89 +/- 0.08 eV for SU+ - S, 1.69 +/- 0.17 eV for U+ - CS, 2.78 +/- 0.33 eV for U+ - CS2, 1.53 +/- 0.30 eV for SU+ - CS, and 5.65 +/- 0.39 eV for S - UCS+. Theory is used to explore the structures and electron configurations of US+, US2+, UCS+, and UCS2+. The thermochemistry measured in this study is further compared to analogous values previously determined for select group 3 metals, lanthanides, and actinides.