Ionic hydration near platinum and liquid mercury surfaces

Molecular Dynamics simulations of a lithium and an iodide ion near a water-platinum and a water-liquid mercury interface have been performed where the ion-metal and the water-metal potentials are derived from ab initio calculations of an ion or a water molecule and a metal cluster consisting of five to ten atoms. The flexible BJH water model and a mercury-mercury potential derived from pseudopotential theory are employed. The other potentials are based on ab initio calculations. The structural properties at the interfaces are described by the ion. oxygen. hydrogen. and mercury density profiles and the ion-oxygen, ion-hydrogen, and ion-mercury radial distribution functions. The mercury-mercury potential allows the analysis of the ion-induced rearrangements of the mercury atoms al the surface. The spectral densities of the hindered translational motions of the ions parallel and perpendicular to the two surfaces are reported.