Surface Penetration without Enrichment: Simulations Show Ion Surface Propensities Consistent with Both Elevated Surface Tension and Surface Sensitive Spectroscopy.
Surface Penetration without Enrichment: Simulations Show Ion Surface Propensities Consistent with Both Elevated Surface Tension and Surface Sensitive Spectroscopy.
复制标题
无需富集的表面渗透：模拟显示离子表面倾向与升高的表面张力和表面敏感光谱一致。
DOI：
10.1021/acs.jpcb.9b04424
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Wang,Feng
中科院分区：
文献类型：
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作者：
Li,Jicun;Wang,Feng
采用分子动力学方法研究了基于mp2力场的NaCl、KBr和CsI溶液中离子的表面倾向。虽然发现NaCl被强烈地排斥在液-气界面之外，但较软的离子，如I -，可以紧密地渗透到界面中。尽管有表面渗透，但界面附近的CsI浓度仍然低于体内的浓度，因此没有表面富集。发现盐浓度会影响离子的相对表面倾向。在较高的盐浓度下观察到更显著的表面渗透。较软离子在较高浓度下形成复杂的多层排列，不能被描述为简单的表面双层。模拟的离子分布解释了具有负表面过剩的软离子的表面扰动的光谱证据，这与盐溶液表面张力的增加相一致。
Molecular dynamics was used to investigate ion surface propensities in NaCl, KBr, and CsI solutions with an MP2-based force field. Although NaCl is found to be strongly repelled from the liquid–vapor interface, softer ions, such as I–, penetrate closely to the interface. Despite the surface penetration, the concentration of CsI near the interface is still lower than that in the bulk, thus leading to no surface enrichment. The salt concentration is found to affect relative surface propensities of the ions. More significant surface penetration is observed at higher salt concentrations. Softer ions at higher concentrations form a complex multilayer arrangement that can not be characterized as a simple surface bilayer. The simulated ion distributions explain the spectroscopic evidence of surface perturbation by soft ions with a negative surface excess consistent with an increased surface tension of salt solutions.