Wilkins David M, Manolopoulos David E, Pipolo Silvio, Laage Damien, Hynes James T
Laboratory of Computational Science and Modeling, IMX, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland.
Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom.
J Phys Chem Lett. 2017 Jun 15;8(12):2602-2607. doi: 10.1021/acs.jpclett.7b00979. Epub 2017 May 30.
We combine classical and ring polymer molecular dynamics simulations with the molecular jump model to provide a molecular description of the nuclear quantum effects (NQEs) on water reorientation and hydrogen-bond dynamics in liquid HO and DO. We show that while the net NQE is negligible in DO, it leads to a ∼13% acceleration in HO dynamics compared to a classical description. Large angular jumps-exchanging hydrogen-bond partners-are the dominant reorientation pathway (just as in a classical description); the faster reorientation dynamics arise from the increased jump rate constant. NQEs do not change the jump amplitude distribution, and no significant tunneling is found. The faster jump dynamics are quantitatively related to decreased structuring of the OO radial distribution function when NQEs are included. This is explained, via a jump model analysis, by competition between the effects of water's librational and OH stretch mode zero-point energies on the hydrogen-bond strength.
我们将经典和环形聚合物分子动力学模拟与分子跳跃模型相结合，以提供对液态HO和DO中水重排和氢键动力学的核量子效应（NQEs）的分子描述。我们表明，虽然净NQE在DO中可以忽略不计，但与经典描述相比，它导致HO动力学加速约13%。大角度跳跃（交换氢键伙伴）是主要的重排途径（就像在经典描述中一样）；更快的重排动力学源于跳跃速率常数的增加。NQEs不会改变跳跃幅度分布，并且未发现明显的隧穿现象。当包含NQEs时，更快的跳跃动力学与OO径向分布函数结构的减少在数量上相关。通过跳跃模型分析，这是由水的摆动和OH伸缩模式零点能量对氢键强度的影响之间的竞争来解释的。
