Molecular mechanism of transporting a polarizable iodide anion across the water-CCl4 liquid/liquid interface.
Molecular mechanism of transporting a polarizable iodide anion across the water-CCl4 liquid/liquid interface.
复制标题
跨水-CCl4 液/液界面传输可极化碘化物阴离子的分子机制。
作者：
C. Wick;L. Dang
本文研究了可极化碘离子在H_2 O-CCl_4液/液界面上的迁移。计算出的平均力的转移自由能分布或势能在吉布斯分界面附近有一个最小值。这些系统的特点是类似的碘化物转移在相应的研究中发现的水蒸气界面;然而，自由能最小值较低的水蒸气界面。还进行了分子动力学模拟，以比较NaCl，NaBr，和碘化钠在水蒸气和H2O-CCl 4界面的浓度。虽然溴离子和碘离子的浓度在H2O-CCl 4界面处比在H2O-蒸汽界面处低，但氯离子浓度在两个界面处相似。碘离子和氯离子的溶剂化结构的分析表明，更极化的碘离子比氯离子在界面处的溶剂化程度低。这一特性使碘离子与CCl 4的接触更紧密，导致与CCl 4的排斥作用，并降低了其向界面移动的趋势。
The result of transferring a polarizable iodide anion across the H2O-CCl4 liquid/liquid interface was investigated in this study. The computed transfer-free energy profile or potential of mean force exhibits a minimum near the Gibbs dividing surface. These system characteristics are similar to those found in a corresponding study of iodide transfer across the H2O-vapor interface; however, the free energy minimum was lower at the H2O-vapor interface. Molecular dynamics simulations were also carried out to compare the concentrations of NaCl, NaBr, and NaI at the H2O-vapor and H2O-CCl4 interfaces. While the concentration of bromide and iodide ions were lower at the H2O-CCl4 interface when compared to the H2O-vapor interface, the chloride ion concentrations were similar at both interfaces. Analysis of the solvation structures of iodide and chloride ions revealed that the more polarizable iodide ion was less solvated than the chloride ion at the interface. This characteristic brought the iodide ion into greater contact with CCl4, resulting in repulsive interactions with CCl4 and reducing its tendency to move to the interface.