title: Fast anomalous diffusion of small hydrophobic species in water.
abstract: Using Car-Parrinello molecular dynamics a structural diffusion mechanism for the simplest hydrophobic species in water, an H atom, is proposed. The hydrophobic solvation cavity is a highly dynamical aggregate that actually drives, by its own hydrogen-bond fluctuations, the diffusion of the enclosed solute. This makes possible an anomalously fast diffusion that falls only short of that of "Grotthuss structural diffusion" of H+ in water. Here, the picture of a static, i.e., "iceberglike," clathrate cage is a misleading concept. The uncovered scenario is similar to the "dynamical hole mechanism" found in a very different context, that is, large molecules moving in hot polymeric melts.
authors.affiliation: Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Kirchner
authors.forename: John
authors.initials: J
authors.lastname: Stubbs
authors.forename: Dominik
authors.initials: D
authors.lastname: Marx
mesh_terms: D004058:Diffusion; D006859:Hydrogen / Q000737:chemistry*; D008958:Models, Molecular; D017510:Protein Folding; D012996:Solutions; D014867:Water / Q000737:chemistry*
chemical_list: D012996:Solutions; D014867:Water; D006859:Hydrogen