title: Reorientation and allied dynamics in water and aqueous solutions.
abstract: The reorientation of a water molecule is important for a host of phenomena, ranging over--in an only partial listing--the key dynamic hydrogen-bond network restructuring of water itself, aqueous solution chemical reaction mechanisms and rates, ion transport in aqueous solution and membranes, protein folding, and enzymatic activity. This review focuses on water reorientation and related dynamics in pure water, and for aqueous solutes with hydrophobic, hydrophilic, and amphiphilic character, ranging from tetra-methylurea to halide ions and amino acids. Attention is given to the application of theory, simulation, and experiment in the probing of these dynamics, in usefully describing them, and in assessing the description. Special emphasis is placed on a novel sudden, large-amplitude jump mechanism for water reorientation, which contrasts with the commonly assumed Debye rotational diffusion mechanism, characterized by small-amplitude angular motion. Some open questions and directions for further research are also discussed.
authors.affiliation: Department of Chemistry, Ecole Normale Supérieure, UMR ENS-CNRS-UPMC 8640, 75005 Paris, France. damien.laage@ens.fr
authors.forename: Damien
authors.initials: D
authors.lastname: Laage
authors.forename: Guillaume
authors.initials: G
authors.lastname: Stirnemann
authors.forename: Fabio
authors.initials: F
authors.lastname: Sterpone
authors.forename: Rossend
authors.initials: R
authors.lastname: Rey
authors.forename: James T
authors.initials: JT
authors.lastname: Hynes