A molecular jump mechanism of water reorientation
A molecular jump mechanism of water reorientation
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DOI：
10.1126/science.1122154
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发表时间：
2006-02-10
期刊：
影响因子：
56.9
通讯作者：
Hynes, JT
中科院分区：
文献类型：
--
作者：
Laage, D;Hynes, JT
尽管进行了长期的研究，但仍然缺乏水重定向机制的分子图像。使用数值模拟，我们发现支持的路径，其中旋转的水分子打破氢键（H-键）与过协调的第一壳邻居形成H-键与欠协调的第二壳邻居。氢键断裂和分子重新取向是协同发生的，而不是通常认为的连续发生的。这种水重定向机制涉及大幅度的角度跳跃，而不是普遍接受的小扩散步骤的序列，因此要求重新解释许多实验数据，其中水旋转松弛被假定为扩散。
Despite long study, a molecular picture of the mechanism of water reorientation is still lacking. Using numerical simulations, we find support for a pathway in which the rotating water molecule breaks a hydrogen bond (H-bond) with an overcoordinated first-shell neighbor to form an H-bond with an undercoordinated second-shell neighbor. The H-bond cleavage and the molecular reorientation occur concertedly and not successively as usually considered. This water reorientation mechanism involves large-amplitude angular jumps, rather than the commonly accepted sequence of small diffusive steps, and therefore calls for reinterpretation of many experimental data wherein water rotational relaxation is assumed to be diffusive.