Prediction of the structures and heats of formation of MO, MO, and MO for M = V, Nb, Ta, Pa.

Structures for the mono-, di-, and tri-bridge isomers of MO as well as those for the MO and MO fragments for M = V, Nb, Ta, and Pa were optimized at the density functional theory (DFT) level. Single point CCSD(T) calculations extrapolated to the complete basis set (CBS) limit at the DFT geometries were used to predict the energetics. The lowest energy dimer isomer was the di-bridge for M = V and Nb and the tri-bridge for M = Ta and Pa.

Hydrolysis of Small Oxo/Hydroxo Molecules Containing High Oxidation State Actinides (Th, Pa, U, Np, Pu): A Computational Study.

The energetics of hydrolysis reactions for high oxidation states of oxo/hydroxo monomeric actinide species (ThO, PaO, UO, PaO(OH), UO(OH), UO, NpO, NpO(OH), and PuO(OH)) were calculated at the CCSD(T) level. The first step is the formation of a Lewis acid/base adduct with HO (hydration), followed by a proton transfer to form a dihydroxide molecule (hydrolysis); this process is repeated until all oxo groups are hydrolyzed. The physisorption (hydration) for each HO addition was predicted to be exothermic, ca.