Long-range hydrogen-bond structure in aqueous solutions and the vapor-water interface.
Long-range hydrogen-bond structure in aqueous solutions and the vapor-water interface.
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DOI：
10.1063/1.4735267
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发表时间：
2012-07
期刊：
影响因子：
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通讯作者：
S. J. Irudayam;Richard H. Henchman
中科院分区：
文献类型：
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作者：
S. J. Irudayam;Richard H. Henchman
关于溶质对水结构的扰动程度，存在着相当大的分歧。一方面，直接分析结构的研究仅显示溶质的第一和可能的第二水化壳层中的局部结构。另一方面，热力学和动力学数据间接地暗示结构化发生在更远的地方。在这里，氢键结构的水周围的卤素阴离子，碱金属阳离子，稀有气体溶质，并在蒸汽-水界面的研究使用分子动力学模拟。除了在第一水化壳层中的预期扰动之外，在模拟盒的其余部分中在较长范围内观察到与本体行为的偏差。特别是，在较长的范围内，有一个过量的受体周围的卤素阴离子，过量的捐助者周围的碱金属阳离子，弱增强四面体和振荡的过剩和不足的捐助者和受体周围的稀有气体溶质，并增强四面体在蒸汽-水界面。结构补偿短程扰动水-水氢键引起的溶质。它不是被限制在溶质附近，而是分散在尽可能多的水分子上，大概是为了最小化对每个水分子的扰动。
There is a considerable disagreement about the extent to which solutes perturb water structure. On the one hand, studies that analyse structure directly only show local structuring in a solute's first and possibly second hydration shells. On the other hand, thermodynamic and kinetic data imply indirectly that structuring occurs much further away. Here, the hydrogen-bond structure of water around halide anions, alkali cations, noble-gas solutes, and at the vapor-water interface is examined using molecular dynamics simulations. In addition to the expected perturbation in the first hydration shell, deviations from bulk behavior are observed at longer range in the rest of the simulation box. In particular, at the longer range, there is an excess of acceptors around halide anions, an excess of donors around alkali cations, weakly enhanced tetrahedrality and an oscillating excess and deficiency of donors and acceptors around noble-gas solutes, and enhanced tetrahedrality at the vapor-water interface. The structuring compensates for the short-range perturbation in water-water hydrogen bonds induced by the solute. Rather than being confined close to the solute, it is spread over as many water molecules as possible, presumably to minimize the perturbation to each water molecule.