Effect of Size on Electron Transfer to Silver Clusters

Abstract

The electronic properties of silver clusters containing up to eight atoms and adsorbed to a positive kink on the (001) surface of silver bromide in contact with aqueous solution are calculated. The necessary reorganization energies and standard free energies of reaction are computed so that the activation energy for transferring an electron from a reducing molecule in solution to silver clusters could be determined with diabatic Marcus electron transfer theory for different cluster sizes. The activation energy oscillates between odd- and even-sized neutral clusters and decreases with increasing size. In the presence of aqueous silver ions, a minimum cluster size of four atoms can be deduced for electron transfer from several reducing agents. These calculated results are discussed in relation to many experimental results. The calculations involve a self-consistent density functional method used to obtain solid state properties of the adsorbed silver clusters and a continuum solvation model (IEF-PCM) used t...