title: A coupled Car-Parrinello molecular dynamics and EXAFS data analysis investigation of aqueous Co(2+).
abstract: We have studied the microscopic solvation structure of Co(2+) in liquid water by means of density functional theory (DFT)-based Car-Parrinello molecular dynamics (CPMD) simulations and extended X-ray absorption fine structure (EXAFS) data analysis. The effect of the number of explicit water molecules in the simulation box on the first and second hydration shell structures has been considered. Classical molecular dynamics simulations, using an effective two-body potential for Co(2+)-water interactions, were also performed to show box size effects in a larger range. We have found that the number of explicit solvent molecules has a marginal role on the first solvation shell structural parameters, whereas larger boxes may be necessary to provide a better description of the second solvation shell. Car-Parrinello simulations were determined to provide a reliable description of structural and dynamical properties of Co(2+) in liquid water. In particular, they seem to describe both the first and second hydration shells correctly. The EXAFS signal was reconstructed from Car-Parrinello simulations. Good agreement between the theoretical and experimental signals was observed, thus strengthening the microscopic picture of the Co(2+) solvation properties obtained using first-principle simulations.
authors.affiliation: Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement, UMR-CNRS 8587, Université d'Evry Val d'Essonne, Boulevard F. Mitterrand, 91025 Evry Cedex, France.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Spezia
authors.forename: Magali
authors.initials: M
authors.lastname: Duvail
authors.forename: Pierre
authors.initials: P
authors.lastname: Vitorge
authors.forename: Thierry
authors.initials: T
authors.lastname: Cartailler
authors.forename: Jeanine
authors.initials: J
authors.lastname: Tortajada
authors.forename: Giovanni
authors.initials: G
authors.lastname: Chillemi
authors.forename: Paola
authors.initials: P
authors.lastname: D'Angelo
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Gaigeot
mesh_terms: D002413:Cations, Divalent / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D010100:Oxygen / Q000737:chemistry; D012996:Solutions; D014867:Water / Q000737:chemistry
chemical_list: D002413:Cations, Divalent; D012996:Solutions; D014867:Water; D003035:Cobalt; D006859:Hydrogen; D010100:Oxygen