Piskulich Zeke A, Laage Damien, Thompson Ward H
Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
PASTEUR, Départment de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, Paris 75005, France.
J Chem Phys. 2020 Aug 21;153(7):074110. doi: 10.1063/5.0020015.
Hydrogen-bond exchanges drive many dynamical processes in water and aqueous solutions. The extended jump model (EJM) provides a quantitative description of OH reorientation in water based on contributions from hydrogen-bond exchanges, or jumps, and the "frame" reorientation of intact hydrogen-bond pairs. Here, we show that the activation energies of OH reorientation in bulk water can be calculated accurately from the EJM and that the model provides a consistent picture of hydrogen-bond exchanges based on molecular interactions. Specifically, we use the recently developed fluctuation theory for dynamics to calculate activation energies, from simulations at a single temperature, of the hydrogen-bond jumps and the frame reorientation, including their decompositions into contributions from different interactions. These are shown to be in accord, when interpreted using the EJM, with the corresponding activation energies obtained directly for OH reorientation. Thus, the present results demonstrate that the EJM can be used to describe the temperature dependence of reorientational dynamics and the underlying mechanistic details.
氢键交换驱动着水和水溶液中的许多动力学过程。扩展跳跃模型（EJM）基于氢键交换（即跳跃）以及完整氢键对的“框架”重排的贡献，对水中OH的重新取向提供了定量描述。在此，我们表明，基于EJM可以准确计算本体水中OH重新取向的活化能，并且该模型基于分子相互作用提供了氢键交换的一致图景。具体而言，我们使用最近开发的动力学涨落理论，从单一温度下的模拟计算氢键跳跃和框架重排的活化能，包括将它们分解为不同相互作用的贡献。当使用EJM进行解释时，这些结果与直接获得的OH重新取向的相应活化能一致。因此，目前的结果表明，EJM可用于描述重新取向动力学的温度依赖性以及潜在的机理细节。
