Probing Interfacial Effects on Ionization Energies: The Surprising Banality of Anion–Water Hydrogen Bonding at the Air/Water Interface
Probing Interfacial Effects on Ionization Energies: The Surprising Banality of Anion–Water Hydrogen Bonding at the Air/Water Interface
复制标题
探究界面对电离能的影响：空气/水界面上阴离子与水氢键的惊人平庸
DOI：
10.1021/jacs.1c03131
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发表时间：
2021
影响因子：
15
通讯作者：
Herbert, John M.
中科院分区：
文献类型：
--
作者：
Paul, Suranjan K.;Herbert, John M.
液体微射流光电子能谱是一种越来越常见的测量水溶质垂直电离能 (VIE) 的技术，但这些实验的解释受到有关本体溶剂化环境与界面溶剂化环境敏感性的问题的影响。我们结合分子动力学模拟和电子结构计算，计算了一组无机阴离子的水相 VIE，无论模拟数据仅限于空气/水界面的离子还是本体水溶液中的离子，结果都与实验非常吻合。尽管计算出的 VIE 对离子-水氢键很敏感，但我们发现两种环境中的短程溶剂化结构非常相似，事实证明不可能根据 VIE 区分两者，这一结论对液相光电子能谱的解释具有重要意义。更一般地说，对模拟数据的分析表明，软阴离子的表面活性很大程度上是第二或第三溶剂化层效应，由水-水氢键的破坏引起，而不是由第一层阴离子-水氢键的显着变化引起。
Liquid microjet photoelectron spectroscopy is an increasingly common technique to measure vertical ionization energies (VIEs) of aqueous solutes, but the interpretation of these experiments is subject to questions regarding sensitivity to bulk versus interfacial solvation environments. We have computed aqueous-phase VIEs for a set of inorganic anions, using a combination of molecular dynamics simulations and electronic structure calculations, with results that are in excellent agreement with experiment regardless of whether the simulation data are restricted to ions at the air/water interface or to those in bulk aqueous solution. Although the computed VIEs are sensitive to ion–water hydrogen bonding, we find that the short-range solvation structure is sufficiently similar in both environments that it proves impossible to discriminate between the two on the basis of the VIE, a conclusion that has important implications for the interpretation of liquid-phase photoelectron spectroscopy. More generally, analysis of the simulation data suggests that the surface activity of soft anions is largely a second or third solvation shell effect, arising from disruption of water–water hydrogen bonds and not from significant changes in first-shell anion–water hydrogen bonding.