Institute for Computational Physics, University of Stuttgart, D-70569 Stuttgart, Germany.
J Phys Chem B. 2020 Mar 19;124(11):2191-2197. doi: 10.1021/acs.jpcb.9b10886. Epub 2020 Mar 11.
We study the principles behind specific ion effects of alkali and halide ions in various protic and aprotic solvents by means of a conceptual density functional theory (DFT) approach. The results of our calculations are in good agreement with experimental data and underline the crucial role of frontier molecular orbital energies. Further analysis reveals that the electronegativities and chemical hardness values of the considered ion and solvent species provide a molecular rationale for specific ion effects and the law of matching water affinities. Based on the analytical expressions and DFT calculations, we show that solvent affinities and the occurrence of specific ion effects, among other molecular mechanisms and interactions, are mainly due to electronegativity differences between the ions and the surrounding solvent molecules.
我们通过概念性密度泛函理论（DFT）方法研究了在各种质子和非质子溶剂中碱金属和卤化物离子的特殊离子效应背后的原理。我们的计算结果与实验数据吻合良好，突出了前沿分子轨道能量的关键作用。进一步的分析表明，所考虑的离子和溶剂物种的电负性和化学硬度值为特殊离子效应和匹配水亲和力定律提供了分子依据。基于解析表达式和 DFT 计算，我们表明溶剂亲和力和特殊离子效应的发生等分子机制和相互作用主要归因于离子与周围溶剂分子之间的电负性差异。
