Emergence of Solvent-Separated Na+-Cl- Ion Pair in Salt Water: Photoelectron Spectroscopy and Theoretical Calculations
Emergence of Solvent-Separated Na+-Cl- Ion Pair in Salt Water: Photoelectron Spectroscopy and Theoretical Calculations
复制标题
盐水中溶剂分离的 Na -Cl- 离子对的出现：光电子能谱和理论计算
DOI：
10.1021/acs.jpclett.6b02670
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发表时间：
2017-01-05
影响因子：
5.7
通讯作者：
Zheng, Wei-Jun
中科院分区：
文献类型：
--
作者：
Hou, Gao-Lei;Liu, Cheng-Wen;Zheng, Wei-Jun
盐在水中的溶剂化是一个基本的物理化学过程，但其基本机理尚不清楚。利用阴离子光电子能谱和从头计算方法研究了NaCI（H2O）簇中接触离子对（CIP）到溶剂分离离子对（SSIP）的跃迁。发现在n = 2时，NaCI-(H2O)阴离子出现了SSIP型结构。对于中性nai (H2O)，当n < 9时，CIP结构占主导地位。在n = 9 ~ 12时，NaCI（H2O）的CIP结构和SSIP结构在能量上接近简并，与NaCI饱和溶液的H2O:NaCI摩尔比一致，表明CIP和SSIP结构在浓溶液中可以共存。这些结果有助于在分子水平上理解盐的溶剂化作用。
Solvation of salts in water is a fundamental physical chemical process, but the underlying mechanism remains unclear. We investigated the contact ion pair (CIP) to solvent-separated ion pair (SSIP) transition in NaCI(H2O) clusters with anion photoelectron spectroscopy and ab initio calculations. It is found that the SSIP type of structures show up at n = 2 for NaCI-(H2O) anions. For neutral NaCI(H2O), the CIP structures are dominant at n < 9. At n = 9-12, the CIP structures and SSIP structures of NaCI(H2O) are nearly degenerate in energy, coincident to the H2O:NaCI molar ratio of NaCI saturated solution and implying that the CIP and SSIP structures can coexist in concentrated solutions. These results are useful for understanding the solvation of salts at the molecular level.