title: Structural progression in clusters of ionized water, (H2O)n=1-5(+).
abstract: Ionized water clusters serve as a model of water-splitting chemistry for energetic purposes, as well as postradiolytic events in condensed-phase systems. Structures, properties, and relative energies are presented for oxidized water clusters, (H2O)n=1-5(+), using equation-of-motion coupled-cluster theory approaches. In small clusters, an ion-radical contact pair OH···H3O+ is known to form upon ionization. The transition from n = 4 to n = 5 molecules in the cluster, however, is found to demarcate a size regime in which a propensity for the ion and radical to separate exists. This trend is consistent with recent experimental vibrational analyses. Decomposition of the cluster energetics reveals that preferential solvation of the hydronium cation by water serves as the dominant driving force for this pair separation, which should persist in larger clusters and bulk water ionization.
authors.affiliation: Henry Eyring Center for Theoretical Chemistry, Thatcher Building for Biological and Biophysical Chemistry, University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112, United States.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Herr
authors.forename: Justin
authors.initials: J
authors.lastname: Talbot
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Steele
mesh_terms: D007477:Ions / Q000737:chemistry; D015394:Molecular Structure; D011789:Quantum Theory; D014867:Water / Q000737:chemistry*
chemical_list: D007477:Ions; D014867:Water