Hydronium ion at the water/1,2-dichloroethane interface: Structure, thermodynamics, and dynamics of ion transfer
Hydronium ion at the water/1,2-dichloroethane interface: Structure, thermodynamics, and dynamics of ion transfer
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DOI：
10.1063/1.5116008
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发表时间：
2019-09-07
影响因子：
4.4
通讯作者：
Benjamin, Ilan
中科院分区：
文献类型：
--
作者：
Benjamin, Ilan
分子动力学模拟，包括伞状取样自由能计算，被用来研究经典离子(H3O+)通过水/1，2-二氯乙烷界面转移的结构、热力学和动力学。计算的转移自由能(17+/-1千卡/摩尔)略大于实验值(14千卡/摩尔)。给出了水化结构的详细分析，并计算了一些动力学性质，它们是沿界面法线距离的函数。特别是，研究表明，离子以本征物种的形式转移，虽然三个水化壳层水分子的平均结构在转移过程中是保守的，但它们可以与附近的水分子交换，交换的速率随着离子进入有机相而降低。
Molecular dynamics simulations including umbrella sampling free energy calculations are used to examine the structure, thermodynamics, and dynamics that accompany the transfer of the classical hydronium ion (H3O+) across the water/1,2-dichloroethane interface. The calculated free energy of transfer (17 +/- 1 kcal/mol) is somewhat larger than the experimental value (14 kcal/mol). A detailed examination of the hydration structure is provided, and several dynamical properties as a function of the distance along the interface normal are calculated. In particular, it is shown that the hydronium ion is transferred as an Eigen species, and while the three hydration shell water molecules' average structure is conserved during the transfer, they may be exchanged with nearby water molecules with a rate that decreases as the ion enters the organic phase.