A COMPUTER-SIMULATION STUDY OF IODIDE-ION SOLVATION IN THE VICINITY OF A LIQUID WATER METAL INTERFACE

The density distribution of an iodide ion in the vicinity of a water/platinum interface has been calculated by classical molecular dynamics simulations based on pairwise additive interaction potentials. The approach of the iodide ion to the surface is strongly sterically hindered by the layer of adsorbed water molecules. Based upon the interaction potentials used in the present study, this steric effect is overcompensated by the direct ion-surface interaction, leading to a significant free energy gain upon contact adsorption. This result is consistent with recent scanning tunneling microscopy investigations of the iodine adsorption on platinum surfaces from aqueous solution.