Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States.
J Phys Chem B. 2022 Aug 4;126(30):5706-5714. doi: 10.1021/acs.jpcb.2c03956. Epub 2022 Jul 21.
Molecular dynamics simulations are used to examine in detail the structure, thermodynamics, and dynamics involve in the adsorption and transfer of the thiocyanate ion (SCN) across the water/toluene interface. Free energy, hydration structure, and several dynamical properties as a function of the ion location along the interface normal are calculated and contrasted with recent experiments. The free energy profile exhibits a local minimum near the interface corresponding to adsorption free energy relative to bulk water of -6 kJ/mol, in reasonable agreement with experiments. The simulations provide insight into the water surface fluctuations that are coupled to the ion transfer, demonstrating formation of water finger-like structures assisting the transfer process.
分子动力学模拟被用来详细研究硫氰酸根离子（SCN）在水/甲苯界面上的吸附和转移过程中的结构、热力学和动力学。计算了自由能、水合结构和几个动力学性质作为离子沿界面法向位置的函数，并与最近的实验进行了对比。自由能曲线在界面附近呈现出一个局部最小值，对应于相对于 bulk water 的吸附自由能为-6 kJ/mol，与实验结果相符合。模拟结果提供了对与离子转移相关的水表面波动的深入了解，表明形成了水指状结构，有助于转移过程。
