A relativistic DFT study of water adsorption on δ-plutonium (1 1 1) surface

Scalar-relativistic DFT-GGA has been used to study adsorption of water in molecular and dissociative configurations on δ-Pu (1 1 1) surface. In molecular state, water is physisorbed in an almost flat-lying orientation at a onefold coordinated on-top site. The interaction of the water 1b1 orbital and the Pu-6d orbital provides the stability of water on the surface, implying that the Pu-5f electrons remain chemically inert. The co-adsorption cases of partially dissociated and fully dissociated products at the threefold hollow sites yield chemisorption, coupled with rumpling of the surface layer and delocalization of the Pu-5f electrons and formation of strong ionic bonds.