Dynamics of Coordinated Water: A Comparison of Experiment and Simulation Results a

Dynamics of Coordinated Water: A Comparison of Experiment and Simulation Results a
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协调水动力学:实验与模拟结果的比较

DOI:
10.1111/j.1749-6632.1986.tb20942.x
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发表时间:
1986
期刊:
影响因子:
--
通讯作者:
R. Impey
R. Impey
中科院分区:
--
文献类型:
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作者:
P. Madden;R. Impey

文献摘要

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水溶液中水分子在离子附近的改变行为及其对溶液宏观物理性质的影响是物理化学长期关注的问题之一。通过将观察到的离子对宏观性质的影响与Frank和他介绍的经典水化壳模型预测的结果进行比较,从现象学的角度来看,离子被认为是“结构制造”或“结构破坏”。这种分类已被证明是在广泛的实验中预测趋势的最有用的指南,但建立一个共同的定量描述已被证明更加困难。通过直接检查来证实这些概念的尝试,在分子水平上,一个离子周围的水分子的状态是相对较新的;最值得注意的是赫兹(核磁共振)、恩德比和尼尔森(中子和X射线)以及他们同事的工作。在离子与其他分子的相互作用(如电子转移反应)或离子与较大物体(如蛋白质、膜和电极)的相互作用的背景下,也讨论了离子周围的水环境。计算机模拟研究在帮助把这些不同的实验研究领域所获得的信息集中起来方面提供了很多帮助。在这篇文章中,我们将描述如何将碱离子和卤化物离子在水中的模拟结果与电解质溶液的分子水平实验结果联系在一起,并用于将出现的图像与经典水合作用概念联系起来。由于恩德比和同事在离子溶液中进行了全面的中子衍射实验,利用同位素差分技术,得到了离子周围水分子排列的详细信息。将这些数据与仿真结果进行了比较
The modified behavior of the water molecules in the vicinity of an ion in aqueous solution and its influence on the macroscopic physical properties of the solution is one of the long-standing interests of physical chemistry.’ Ions have been recognized as “structure-making” or “structure-breaking” in a phenomenological way, by comparing their observed effect upon the macroscopic properties with that predicted by the classical hydration shell models introduced by Frank and This categorization has proven a most useful guide to predicting trends in a wide range of experiments, but the establishment of a common quantitative description has proven more difficult. Attempts to substantiate these concepts by directly examining, a t the molecular level, the state of the water molecules around an ion are relatively recent; most notable is the work of Hertz4 (NMR) and Enderby and Nielson’ (neutrons and X rays) and their coworkers. The aqueous environment around an ion is also discussed in the context of the interaction of ions with other molecules, as in electron-transfer reactions, or in their interaction with larger bodies, such as proteins, membranes, and electrodes6 Computer simulation studies have much to offer in helping to bring together the information that is available from these different strands of experimental investigation. In this article we will describe how the results of simulations of alkali and halide ions in water have been tied together with the results of molecular-level experiments on electrolyte solutions and used to relate the picture that emerges to the classical concept of hydration. Thanks to the comprehensive neutron diffraction experiments, using the isotope difference technique, which have been performed on ionic solutions by Enderby and coworker^,^*^ detailed information on the arrangement of the water molecules around an ion is available. The comparison of these data with simulation results has already