Energy transfer within the hydrogen bonding network of water following resonant terahertz excitation
Energy transfer within the hydrogen bonding network of water following resonant terahertz excitation
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DOI：
10.1126/sciadv.aay7074
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发表时间：
2020-04-01
期刊：
影响因子：
13.6
通讯作者：
Sajadi, Mohsen
中科院分区：
文献类型：
--
作者：
Elgabarty, Hossam;Kampfrath, Tobias;Sajadi, Mohsen
与许多其他液体相比，水中的能量耗散非常快且效率更高。这种行为通常归因于与氢键相关的分子间相互作用。在这里，我们通过泵探针实验研究了液态水氢键网络中的动态能量流。我们用超短单周期太赫兹脉冲共振激发分子间自由度并监测其拉曼响应。通过使用超薄样品池窗口，可以获得尾部单指数弛豫的无背景双极性信号。使用互补实验、力场和从头算分子动力学模拟，弛豫归因于分子平移运动。他们揭示了太赫兹电场与分子旋转自由度的初始耦合，分子旋转自由度的能量在激发脉冲持续时间内快速转移到相邻分子的受限平移运动。这种快速的能量转移可以通过分子间相互作用的强非和谐性来合理化。
Energy dissipation in water is very fast and more efficient than in many other liquids. This behavior is commonly attributed to the intermolecular interactions associated with hydrogen bonding. Here, we investigate the dynamic energy flow in the hydrogen bond network of liquid water by a pump-probe experiment. We resonantly excite intermolecular degrees of freedom with ultrashort single-cycle terahertz pulses and monitor its Raman response. By using ultrathin sample cell windows, a background-free bipolar signal whose tail relaxes monoexponentially is obtained. The relaxation is attributed to the molecular translational motions, using complementary experiments, force field, and ab initio molecular dynamics simulations. They reveal an initial coupling of the terahertz electric field to the molecular rotational degrees of freedom whose energy is rapidly transferred, within the excitation pulse duration, to the restricted translational motion of neighboring molecules. This rapid energy transfer may be rationalized by the strong anharmonicity of the intermolecular interactions.