Department of Chemistry, University of California, Berkeley, California 94705, USA.
J Chem Phys. 2017 Aug 14;147(6):064301. doi: 10.1063/1.4997046.
Theoretical studies of hydrogen bond network rearrangement (HBNR) dynamics in liquid water have indicated that librational motions initiate the hydrogen bond breaking/formation processes. We present the results of using a simple time evolution method to extract and compare the tunneling lifetimes for motions that break and reform the hydrogen bond for the water dimer, trimer, and pentamer from the experimentally measured tunneling splittings in the ground and excited intermolecular vibrational states. We find that the specific nature of the intermolecular vibrational excitation does not significantly influence the tunneling lifetime of the dimer, but that only excitations to a librational vibration affect the water trimer and pentamer lifetimes. The specific enhancement of bifurcation tunneling in larger clusters relative to the dimer also indicates that hydrogen bond cooperativity is a vital element of these dynamics.
氢键网络重排（HBNR）动力学的理论研究表明，振动运动引发了氢键的断裂/形成过程。我们提出了一种简单的时间演化方法的结果，用于从实验测量的氢键断裂和形成的水二聚体、三聚体和五聚体的基态和激发分子间振动态的隧道分裂中提取和比较用于断裂和形成氢键的运动的隧道寿命。我们发现，分子间振动激发的特定性质不会显著影响二聚体的隧道寿命，但只有激发到振动运动才会影响三聚体和五聚体的寿命。与二聚体相比，较大簇中的分叉隧道的特定增强也表明氢键协同作用是这些动力学的重要组成部分。
