title: Multi-scale modelling of uranyl chloride solutions.
abstract: Classical molecular dynamics simulations with explicit polarization have been successfully used to determine the structural and thermodynamic properties of binary aqueous solutions of uranyl chloride (UO2Cl2). Concentrated aqueous solutions of uranyl chloride have been studied to determine the hydration properties and the ion-ion interactions. The bond distances and the coordination number of the hydrated uranyl are in good agreement with available experimental data. Two stable positions of chloride in the second hydration shell of uranyl have been identified. The UO2(2+)-Cl(-) association constants have also been calculated using a multi-scale approach. First, the ion-ion potential averaged over the solvent configurations at infinite dilution (McMillan-Mayer potential) was calculated to establish the dissociation/association processes of UO2 (2+)-Cl(-) ion pairs in aqueous solution. Then, the association constant was calculated from this potential. The value we obtained for the association constant is in good agreement with the experimental result (KUO2Cl(+) = 1.48 l mol(-1)), but the resulting activity coefficient appears to be too low at molar concentration.
authors.affiliation: Institut de Chimie Séparative de Marcoule (ICSM), UMR 5257, CEA-CNRS-Université Montpellier 2-ENSCM, Site de Marcoule, Bâtiment 426, BP 17171, F-30207 Bagnols-sur-Cèze Cedex, France.
authors.forename: Thanh-Nghi
authors.initials: TN
authors.lastname: Nguyen
authors.affiliation: Institut de Chimie Séparative de Marcoule (ICSM), UMR 5257, CEA-CNRS-Université Montpellier 2-ENSCM, Site de Marcoule, Bâtiment 426, BP 17171, F-30207 Bagnols-sur-Cèze Cedex, France.
authors.forename: Magali
authors.initials: M
authors.lastname: Duvail
authors.affiliation: Institut de Chimie Séparative de Marcoule (ICSM), UMR 5257, CEA-CNRS-Université Montpellier 2-ENSCM, Site de Marcoule, Bâtiment 426, BP 17171, F-30207 Bagnols-sur-Cèze Cedex, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Villard
authors.affiliation: Fukui Institute for Fundamental Chemistry, Kyoto University, Takano-Nishihiraki-cho 34-4, Sakyo-ku, Kyoto 606-8103, Japan.
authors.forename: John Jairo
authors.initials: JJ
authors.lastname: Molina
authors.affiliation: CEA/DEN/DRCP/SMCS/LILA, Marcoule, F-30207 Bagnols-sur-Cèze Cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Guilbaud
authors.affiliation: Institut de Chimie Séparative de Marcoule (ICSM), UMR 5257, CEA-CNRS-Université Montpellier 2-ENSCM, Site de Marcoule, Bâtiment 426, BP 17171, F-30207 Bagnols-sur-Cèze Cedex, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Dufrêche