Water Clusters: Fascinating Hydrogen-Bonding Networks, Solvation Shell Structures, and Proton Motion

Structure, energetics, and dynamics of protonated water clusters (H 2 O) n H + ( n = 1,8) are studied with first-principles Born−Oppenheimer molecular dynamics simulations. Two solvation shell structures, centered at H + and H 3 O +, respectively, are found to be nearly equivalent energetically. However, the dynamical and thermodynamical characteristics of these two competing structures are very different. Patterns of hydrogen-bonded networks as well as the mechanisms of proton transfer are revealed via systematic investigations.