Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Faraday Discuss. 2013;160:89-101; discussion 103-20. doi: 10.1039/c2fd20113e.
Although there is a consensus that large, polarizable anions will adsorb to the air-water interface, the precise interactions that give rise to surface enhancement are still being debated. Previously, we have demonstrated that there is a significant dependence on the choice of molecular interaction potential for I-adsorption at the air-water interface. Specifically, density functional theory (DFT) based interaction potentials lead to significantly less adsorption than empirical interaction potentials that include polarization. We have also demonstrated that DFT based interaction potentials can accurately capture the structure of the first solvation shell of both simple and polyatomic anions as compared to multi-edge X-ray absorption fine structure (XAFS) experiments. We utilize DFT to examine the local hydration structure of SCN- and IO3- that exhibit both chaotropic and kosmotropic characteristics. We compare and contrast the solvation structure of the polyatomic anions with the series of halide anions. A picture emerges where we can correlate local solvation structure to the ions' position in the Hofmeister series.
虽然人们普遍认为大的、可极化的阴离子会吸附在气-水界面上，但导致表面增强的确切相互作用仍在争论中。以前，我们已经证明，在气-水界面上 I-的吸附对分子相互作用势能的选择有很大的依赖性。具体来说，基于密度泛函理论 (DFT) 的相互作用势能导致的吸附量明显小于包括极化的经验相互作用势能。我们还证明，与多边缘 X 射线吸收精细结构 (XAFS) 实验相比，基于 DFT 的相互作用势能可以准确地捕获简单和多原子阴离子的第一溶剂化壳的结构。我们利用 DFT 来研究 SCN-和 IO3-的局部水合结构，它们都表现出反溶和正溶的特性。我们比较和对比了多原子阴离子与一系列卤化物阴离子的溶剂化结构。出现了这样一种情况，我们可以将局部溶剂化结构与离子在 Hofmeister 序列中的位置相关联。
