Ojha Deepak, Karhan Kristof, Kühne Thomas D
Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, Paderborn University, Warburger Str. 100, D-33098, Paderborn, Germany.
Paderborn Center for Parallel Computing and Institute for Lightweight Design, Paderborn University, Warburger Str. 100, D-33098, Paderborn, Germany.
Sci Rep. 2018 Nov 15;8(1):16888. doi: 10.1038/s41598-018-35357-9.
In the present work, we introduce two new metrics i.e. hydrogen-bond strength and charge-transfer between the donor/acceptor water molecules as a measure of hydrogen-bond rearrangement dynamics. Further, we also employ a simple model based on energy flux through the donor-acceptor water pairs to quantify the extent of the local hydrogen-bond network reorganization. Most importantly, we report a linear relationship between the OH stretch frequency and the charge and energy transfer through donor-acceptor water pairs. We demonstrate that the vibrational frequency fluctuations, which are used to determine third-order non-linear spectroscopic observables like the short-time slope of three pulse photon echo, can be used as an analog of the fluctuations in the hydrogen-bond strength and charge-transfer. The timescales obtained from our hydrogen-bond strength correlation and charge-transfer correlation decay are in excellent agreement with the computed frequency-time correlation function, as well as with recent vibrational echo experiments.
在本工作中，我们引入了两个新的度量标准，即供体/受体水分子之间的氢键强度和电荷转移，以此作为氢键重排动力学的一种度量。此外，我们还采用了一个基于通过供体-受体水对的能量通量的简单模型，来量化局部氢键网络重组的程度。最重要的是，我们报告了OH伸缩频率与通过供体-受体水对的电荷和能量转移之间的线性关系。我们证明，用于确定三阶非线性光谱可观测量（如三脉冲光子回波的短时斜率）的振动频率波动，可以用作氢键强度和电荷转移波动的类似物。从我们的氢键强度相关性和电荷转移相关性衰减中获得的时间尺度，与计算得到的频率-时间相关函数以及最近的振动回波实验结果非常吻合。
