Ion hydration: Thermodynamic and structural analysis with an integral equation theory of liquids
Ion hydration: Thermodynamic and structural analysis with an integral equation theory of liquids
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DOI：
10.1021/jp9608786
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发表时间：
1997-04-17
影响因子：
3.3
通讯作者：
Hirata, F
中科院分区：
文献类型：
--
作者：
Chong, SH;Hirata, F
我们提出了一个离子水合的积分方程方法的基础上的扩展参考相互作用网站方法（ex-RISM）的理论研究。我们分析了溶剂化的热力学函数，特别是在无限稀释的个别离子的偏摩尔体积。特别注意的是偏摩尔体积中所包含的信息和个别离子的偏摩尔体积是否反映了离子-水相互作用的真实性质的问题。我们的结果表明，与Kusalik和Patey以前的工作（J.Chem.Phys.1988，89，5843）相反，偏摩尔体积确实反映了离子-水相互作用的性质。关于离子水合的微观描述，我们重新审视了早期的模型提出的Samoilov定义的激活能Δ E-i在他的模型中的离子-水的平均力的潜力。理论结果与早期的模型在将离子分为“正"和”负"水化方面是雅阁的。我们还讨论了由于利用溶剂分布函数的密度导数的离子的存在下，水的结构变化。观察到“正”和“负”水合离子之间的密度导数的定性差异，并发现与平均力的潜力分析一致。
We present a theoretical study for ion hydration based on an integral equation method referred to as the extended reference interaction site method (ex-RISM). We analyze the thermodynamic functions of solvation, especially the partial molar volumes of individual ions at infinite dilution. Special attention is paid to information contained in the partial molar volumes and to the question of whether the partial molar volumes of individual ions reflect the true nature of ion-water interactions. Our results suggest, contrary to the previous work given by Kusalik and Patey (J. Chem. Phys. 1988, 89, 5843), that the partial molar volumes do reflect the nature of ion-water interactions. Concerning the microscopic description of the ion hydration, we revisit the earlier model proposed by Samoilov by defining the activation energy Delta E-i in his model in terms of the ion-water potential of mean force. The theoretical results are in good accord with the earlier model in terms of the classification of ions into the ''positive'' and ''negative'' hydrations. We also discuss the structural changes of water due to the presence of an ion utilizing the density derivatives of the solvent distribution functions. Qualitative differences of the density derivatives between the ''positively'' and ''negatively'' hydrated ions were observed and found to be consistent with the analysis of the potential of mean force.