PNNL

Abstract

Aqueous complexation, adsorption and redox chemistry of actinide species at mineral surfaces have significant impact on their transport and reactive behaviour in chemically and physically heterogeneous environments. The adsorption configurations and energies of micro-solvated uranyl dication, UO2 2+, on fully hydroxylated and H-deficient a-alumina (0001)-like finite cluster models were studied. The significant size of the models provides faithful representations of features that have emerged from periodic calculations, but most importantly, they afford us a systematic study of the preferred adsorption configurations, effect of secondary solvation shells and explicit treatment of the total charge. The energetics computed from the difference between the optimized structures and the appropriate reference states, point at a preference for inner sphere type complex.