Department of Earth and Environmental Science and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, 19104-6316, United States.
Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.
J Am Chem Soc. 2020 Oct 14;142(41):17329-17333. doi: 10.1021/jacs.0c08994. Epub 2020 Sep 30.
The interaction and orientation of hypochlorous acid (HOCl) on the ice surface has been of great interest as it has important implications to ozone depletion. As HOCl interacts with the ice surface, previous classical molecular dynamics simulations suggest its OH moiety orients to the outside of the ice surface, whereas the quantum calculations performed at 0 K indicate its Cl atom is exposed. To resolve this contradiction, herein, Born-Oppenheimer molecular dynamics simulations are adopted, and the results suggest that at ambient temperature, the interaction between HOCl with interfacial water is dominated by the robust H-bond of (HOCl)H-O(HO). As a result, the HOCl mainly acts as the proton donor to the water surface, which thus can participate in proton transfer reactions via the promotion of interfacial water. Moreover, the Cl atom of HOCl is found to be exposed to the outside of the water surface. Therefore, during the heterogeneous reactions of HOCl on the water surface, the Cl atom becomes the reactive site and is easily attacked by other species.
次氯酸（HOCl）在冰表面的相互作用和取向一直备受关注，因为它对臭氧消耗有重要影响。当 HOCl 与冰表面相互作用时，先前的经典分子动力学模拟表明其 OH 部分朝向冰表面的外部，而在 0 K 下进行的量子计算表明其 Cl 原子暴露在外。为了解决这一矛盾，本文采用 Born-Oppenheimer 分子动力学模拟，结果表明，在环境温度下，HOCl 与界面水之间的相互作用主要由（HOCl）H-O（HO）的强氢键主导。因此，HOCl 主要作为质子供体向水面提供质子，从而可以通过促进界面水参与质子转移反应。此外，还发现 HOCl 的 Cl 原子暴露在水面之外。因此，在 HOCl 在水面上的多相反应中，Cl 原子成为反应位点，很容易受到其他物质的攻击。
