title: Role of Presolvation and Anharmonicity in Aqueous Phase Hydrated Proton Solvation and Transport.
abstract: Results from condensed phase ab initio molecular dynamics (AIMD) simulations suggest a proton transfer reaction is facilitated by "presolvation" in which the hydronium is transiently solvated by four water molecules, similar to the typical solvation structure of water, by accepting a weak hydrogen bond from the fourth water molecule. A new version 3.2 multistate empirical valence bond (MS-EVB 3.2) model for the hydrated excess proton incorporating this presolvation behavior is therefore developed. The classical MS-EVB simulations show similar structural properties as those of the previous model but with significantly improved diffusive behavior. The inclusion of nuclear quantum effects in the MS-EVB also provides an even better description of the proton diffusion rate. To quantify the influence of anharmonicity, a second model (aMS-EVB 3.2) is developed using the anharmonic aSPC/Fw water model, which provides similar structural properties but improved spectroscopic responses at high frequencies.
authors.affiliation: Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Rajib
authors.initials: R
authors.lastname: Biswas
authors.affiliation: Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Ying-Lung Steve
authors.initials: YL
authors.lastname: Tse
authors.affiliation: Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Andrei
authors.initials: A
authors.lastname: Tokmakoff
authors.affiliation: Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Voth