ENERGY COMPONENT ANALYSIS FOR DILUTE AQUEOUS-SOLUTIONS OF LI+, NA+, F-, AND CL- IONS
ENERGY COMPONENT ANALYSIS FOR DILUTE AQUEOUS-SOLUTIONS OF LI+, NA+, F-, AND CL- IONS
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DOI：
10.1021/ja00316a012
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发表时间：
1984-01-01
影响因子：
15
通讯作者：
JORGENSEN, WL
中科院分区：
文献类型：
--
作者：
CHANDRASEKHAR, J;SPELLMEYER, DC;JORGENSEN, WL
蒙特卡罗模拟了Li+， Na+， F“和Cl”在25℃和1atm下的稀水溶液，使用了最近开发的可转移分子间电位函数。计算出的溶液热、溶液体积、配位数和结构结果与现有的实验数据比较一致。计算出的能量被划分为代表(i)溶质-第一溶剂壳层，（ii）溶质-体积溶剂，（iii）第一壳层-第一壳层，（iv）第一壳层-体积和(v)体积-体积相互作用的分量。将这些成分与液态水的相应结果进行比较，可以详细了解不同溶液中溶剂重组的性质，补充氢键分析提供的结构信息。最重要的结构结果是第一溶剂化壳的形成，其溶剂分子表现出净相互排斥。虽然水的正常氢键网络在第一壳层之外迅速建立，但第一壳层与水的相互作用明显受到破坏，特别是在Li+和Na+溶液中。在所有的溶液中，与第一壳层分子相关的重组构成了溶剂总重组能的主要组成部分。离子和第一溶剂壳的能量学也与小离子-水团簇的气相结果进行了比较。考察了这些值在溶液总热变化趋势中的变化程度。在过去的十年中，对电解溶液中溶剂化性质的新见解来自离子分子簇的气相实验。1,2利用从头算量子力学方法对配合物进行了结构表征，补充了以这种方式获得的精确热力学数据。这些结果与稀溶液的结果相似的程度是相当重要的。特别重要的是，要知道在给定的溶剂中，不同离子的溶液热的趋势是如何很好地再现的
Monte Carlo simulations have been carried out on dilute aqueous solutions of Li+, Na+, F", and Cl" at 25 C and1 atm, using recently developed transferable intermolecular potential functions. The calculated heats of solution, volumes of solution, coordination numbers, and structural results compare favorablywith available experimentaldata. The calculated energies have been partitioned into components representing (i) solute-first solvent shell,(ii) solute-bulk solvent,(iii) first shell-first shell,(iv) first shell-bulk, and (v) bulk-bulk interactions. Comparison of these components with the corresponding results obtained for liquid water provides detailed insight into thenature of solvent reorganization in the different solutions, complementing the structural information provided by hydrogen bonding analyses. The most significant structural consequence is the formation of the first solvation shell, whose solvent molecules exhibit net mutual repulsion. Although the normal hydrogen bonding network of water is established rapidly beyond the first shell, some disruption in the first shell-bulk water interaction is evident, particularly in the Li+ and Na+ solutions. In all the solutions, the reorganization associated with the first-shell molecules constitutes the major component of the total solvent reorganization energy. The energetics of the ion and the first solvent shell are also compared with gas-phase results on small ion-water clusters. The degree to which these values follow the trends intotal heats of solution is examined.Fresh insights into the nature of solvation in electrolytic solutions have come in the past decade from gas-phase experiments on ion-molecule clusters. 1, 2 The precise thermodynamic data ob-tained in this way have been complemented by structural char-acterization of the complexes with use of ab initio quantum mechanical methods. 3, 4 The extent to which these results parallel those for dilute solutions is of considerable significance. In particular, it is important to know how well the trends in heats of solution of different ions in a given solvent are reproduced by