Theoretical study of protonated water clusters using the effective fragment potential

Kurt Brorsen, Iowa State University

The structures of protonated water clusters, H+(H2O)N, are studied using a combination of ab initio electronic structure theory and the effective fragment potential (EFP) method. Monte Carlo calculations are performed on H3O+ and H5O2+ solvated by 4, 8, 16, and 32 water molecules. These calculations are initially performed by treating both the cation and water molecules as EFPs. Subsequently, second-order perturbation theory (MP2) and the EFP method are used for the cation and water molecules, respectively. Single point energy calculations are performed in which both the cation and water molecules are treated with MP2. It is found that for all cations and all combinations of theory employed here, the cation prefers to lie on the surface of the cluster.

Abstract Author(s): Kurt R. Brorsen, Theresa L. Windus and Mark S. Gordon