title: Uranyl ion interaction at the water/NiO(100) interface: a predictive investigation by first-principles molecular dynamic simulations.
abstract: The behavior of the UO(2)(2+) uranyl ion at the water/NiO(100) interface was investigated for the first time using Born-Oppenheimer molecular dynamic simulations with the spin polarized DFT + U extension. A water/NiO(100) interface model was first optimized on a defect-free five layers slab thickness, proposed as a reliable surface model, with an explicit treatment of the solvent. Water molecules are adsorbed with a well-defined structure in a thickness of about 4 Å above the surface. The first layer, adsorbed on nickel atoms, remains mainly in molecular form but can partly dissociate at 293 K. Considering low acidic conditions, a bidentate uranyl ion complex was characterized on two surface oxygen species (arising from water molecules adsorption on nickel atoms) with d(U-O(adsorption))=2.39 Å. This complex is stable at 293 K due to iono-covalent bonds with an estimated charge transfer of 0.58 electron from the surface to the uranyl ion.
authors.affiliation: EDF-R&D, Département Matériaux et Mécanique des Composants, Les Renardières, Ecuelles, 77818 Moret Sur Loing, France.
authors.forename: Karim
authors.initials: K
authors.lastname: Sebbari
authors.forename: Jérôme
authors.initials: J
authors.lastname: Roques
authors.forename: Christophe
authors.initials: C
authors.lastname: Domain
authors.forename: Eric
authors.initials: E
authors.lastname: Simoni