Silver–Water Clusters: A Theoretical Description of Agn(H2O)m for n = 1–4; m = 1–4

Abstract

Calculations of the equilibrium structure and thermodynamic properties of first sphere silver–water neutral, cation, and anion clusters Agn(H2O)m, n = 1–4; m = 1–4 are reported. Density functional theory with the PBE1PBE functional is employed to determine stationary points at the global energy minimum. Cation clusters show Ag–O coordination while neutral clusters have Ag–O and Ag–H coordination possessing ring structures with multiple water ligands and having an O–H intermolecular interaction. The anion structures involve Ag–H coordination with ring structures. Properties relevant to nucleation and physical development applications are calculated from the Gibbs free energy at room temperature. The free energies of the clusters indicate a driving force to aggregate, bind silver ion or accept an electron from reducing agents such as O2–. The ability of the silver–water clusters to serve as qualitative models for aqueous phase species was evaluated and found to be a good approximation. Neutral silver–water clusters in solution were found to be energetically favorable for deposition on nucleating centers present in physical development. The silver–water clusters adsorbed to a polarizable crystal surface showed small effects of the water ligands on their ability to accept electrons.