Sigma bond activation of deuterium mediated by atomic cerium cations: Experiment and theory

Abstract Reaction of ground-state Ce + (5d 2 4f 1 ) with deuterium in a reaction cell at a pressure of 1.5–4.0 Torr and temperatures ranging from approximately 265–515 K is studied. Rate constants for formation of CeD 2 + are acquired and vary from approximately 2.8 × 10 −14 to 2.1 × 10 −13  cm 3 /s. A negative temperature dependence is observed for the measured rate constants, indicating the reaction becomes less efficient as the temperature increases, consistent with an exothermic reaction. Electronic structure calculations were performed using density functional theory (DFT) at the PBE0 level to characterize all reactant and product species as well as to generate potential energy surfaces (PESs) for the insertion reaction. This combination of experimental and theoretical results suggest that Ce + inserts into the deuterium sigma bond in an overall exothermic and barrierless process.