Ab initio investigation of the ground and excited states of RuO+,0,‒ and their reaction with water
High level quantum chemical calculations on RuO0,± elucidate the electronic structure of their low-lying electronic states. For thirty-two states, we report electronic configurations, bond lengths, vibrational frequencies, spin-orbit splittings, and excitation energies. The electronic states of RuO can be generated from those of RuO+ by adding one electron to σ non-bonding orbital closely resembling the 5s atomic orbital of Ru. The ground states for RuO and RuO− are clearly identified as 5Δ and 4Δ, but two states (4Δ and 2Π) compete for RuO+. The difficulty of the calculations is reflected by our small binding energies compared to the experimental values. In addition, we studied the reaction of the three species with water in their ground and selected low-lying electronic states. We found a consistent decrease of the activation energy barriers and higher exothermicity as we add electrons to the system. RuO− is found to facilitate the reaction for both kinetic and thermodynamic reasons.