The Electrogeneration of Solvated Metal Atoms. II. Analyses of the Stabilities of Solvated Cations and Atoms

摘要

The purpose of this paper is to investigate mechanical models of ionic and atomic solvation in order to suggest a part of the mechanism of the electroreduction of metal ions. We use a Morse potential, the parameters for which are determined with the use of spectroscopic information, to try to predict the mechanical properties of a solvated atom. In particular, the solvated ionic and atomic systems are allowed to approach and interact with a metallic surface. Changes in the positions of the equilibria and changes in the calculated force constants are determined. We defined accurate adionic and adatomic states. In these states the ion or atom occupies an expanded cage which includes the solvent and the surface of the metal. The activation energies for the formation of adions may be much larger than the activation energies for the formation of the related adatoms. Thus, if a reduction should occur at the outer Helmholtz plane, a solvated atom can be formed. In the vicinity of the surface, such a solvated atom can desolvate much more readily than the ion. The strength with which solvent or ligand is associated with a zero-valent metallic species, we believe, influences strongly the character of the metallic deposit formed.