Vibrational spectroscopy of HOD in liquid D2O.: III.: Spectral diffusion, and hydrogen-bonding and rotational dynamics
Vibrational spectroscopy of HOD in liquid D2O.: III.: Spectral diffusion, and hydrogen-bonding and rotational dynamics
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DOI：
10.1063/1.1525802
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发表时间：
2003-01-01
影响因子：
4.4
通讯作者：
Skinner, JL
中科院分区：
文献类型：
--
作者：
Lawrence, CP;Skinner, JL
时间分辨红外光谱有潜力提供前所未有的关于液体分子动力学的信息。就水而言，正在开发的最令人兴奋的技术之一是瞬态烧孔。在D2O中稀释的氢氧化钠实验中，我们可以得到氢氧化钠拉伸振动的跃迁频率时间相关函数，发现它在0.5到1ps的时间尺度上衰减。在本文中，我们提供了这种光谱扩散时间相关函数的分子水平解释。首先，我们验证了氢键HOD分子的瞬时OH频率与（氢键）D2O分子的距离高度相关。其次，我们发现瞬时OH频率与HOD分子是否具有氢键高度相关。最后，我们证明了光谱扩散时间相关函数的短时间动力学是由于氢键拉伸运动引起的，而实验中观察到的长时间衰减是由于氢键形成和断裂的动力学引起的。我们还提出了理论结果，描述了最近的极化各向异性实验，测量频率相关的旋转动力学。(C) 2003年美国物理研究所。
Time-resolved infrared spectroscopy has the potential to provide unprecedented information about molecular dynamics in liquids. In the case of water, one of the most exciting techniques being developed is transient hole-burning. From experiments on dilute HOD in D2O one can obtain the transition frequency time-correlation function for the OH stretch vibration, finding that it decays on a time scale of between 0.5 and 1 ps. In this paper we provide a molecular-level interpretation of this spectral diffusion time-correlation function. First, we verify that for hydrogen-bonded HOD molecules the instantaneous OH frequency is highly correlated with the distance to the (hydrogen-bonded) D2O molecule. Second, we show that the instantaneous OH frequency is highly correlated with whether or not the HOD molecule has a hydrogen bond. Finally, we show that the short-time dynamics of the spectral diffusion time-correlation function is due to hydrogen-bond stretching motions, while the longer-time decay observed in the experiments is due to the dynamics of forming and breaking hydrogen bonds. We also present theoretical results that describe recent polarization anisotropy experiments, which measure frequency-dependent rotational dynamics. (C) 2003 American Institute of Physics.