A Theoretical investigation on the intermolecular potential curve between ruthenium tetroxide and NO (X = 1, 2)

Kido, Kentaro 

Ruthenium tetroxide (RuO) is one of chemical species of fission products assumed to be released to the environment during a severe accident of nuclear facilities and a target compound to assess the amount produced, reactivity, mobility and release timing. In this article, the NO (X = 1, 2) adduct formation of RuO has been investigated, based on the potential energy curve (PEC) evaluated by UM06, UTPSSh, CASSCF, and CASPT2 methods. At several stationary points, CCSD and LR-CCSD(T) energies are also computed for a comparison. The PEC shows that there is an activation barrier to form the NO adduct and that the process is endothermic in terms of free energy. In the system, the electron transfer occurs from NO to RuO when the bond between the nitrogen and oxo ligand is formed. It has been discussed in detail using active orbitals, weight of electron configurations and spin population obtained by CASSCF.