Abstract

The large amplitude and sudden jump dynamics of a hydrogen (H)-bond’s initial rupture and its subsequent formation of an H-bond with a different partner has been argued to well describe the reorientation dynamics in pure water and in aqueous solutions of a wide variety of solutes ranging from simple ions to complex biomolecules. This description is however a classical one for the nuclear motion, and a concern is the possible effect of the quantum character of the light hydrogens’ motions. Here we will recount the main results of our recent efforts to quantify and understand the impact of such nuclear quantum effects on this issue. To this end, we have employed a ring polymer molecular dynamics (RPMD) description for both H2O and D2O liquids, with particular emphasis on the chemical reaction perspective for the reorientation process. If time permits, we will also describe our initial efforts to combine RPMD and Grote-Hynes theory for reaction rate constants. This research is a collaboration with Damien Laage (ENS), David Manolopoulos (Oxford), and several of their students, as to be detailed in the presentation.