  Scalar-relativistic DFT-GGA has been used to study adsorption of water in
molecular and dissociative configurations on delta-Plutonium (111) surface. In
molecular state, water is physisorbed in an almost flat-lying orientation at a
one-fold 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 three-fold hollow
sites yield chemisorption, coupled with rumpling of the surface layer and
delocalization of the Pu-5f electrons and formation of strong ionic bonds.
