Karimova Natalia V, McCaslin Laura M, Gerber R Benny
Department of Chemistry, University of California, Irvine, CA 92697, USA.
Institute of Chemistry, Fritz Haber Research Center, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Faraday Discuss. 2019 Jul 18;217(0):342-360. doi: 10.1039/c8fd00230d.
Reactions of nitrogen oxides with seawater are of major atmospheric importance, but microscopic understanding of these processes is still largely unavailable. In this paper we explore models of reactions of N2O4 with ions in water in order to provide molecular-level understanding of the processes. Presented here are studies of N2O4 interacting with two ions, SO42- and Cl-, in small water clusters. Reactions of the asymmetric conformer of N2O4 with SO42- ions in water clusters are studied via ab initio molecular dynamics (AIMD) simulations in order to unravel the microscopic mechanism of the processes and predict the timescales of different steps. Spectroscopic signatures of the reaction are proposed. The mechanisms of chloride substitution and hydrolysis of symmetric and asymmetric N2O4 are explored via intrinsic reaction coordinate (IRC) calculations. Spectroscopic calculations for relevant species suggest possible experimental signatures for the processes. The results of these model ion-N2O4 reactions in water throw light on the molecular-level mechanisms of the reactions of nitrogen oxides with seawater.
氮氧化物与海水的反应在大气中具有重要意义，但目前对这些过程的微观理解仍十分匮乏。在本文中，我们探究了N₂O₄与水中离子的反应模型，以便从分子层面理解这些过程。本文展示了对N₂O₄与小水簇中的两种离子（SO₄²⁻和Cl⁻）相互作用的研究。通过从头算分子动力学（AIMD）模拟研究了水簇中N₂O₄的不对称构象与SO₄²⁻离子的反应，以揭示这些过程的微观机制并预测不同步骤的时间尺度。提出了该反应的光谱特征。通过内禀反应坐标（IRC）计算探索了对称和不对称N₂O₄的氯化取代和水解机制。对相关物种的光谱计算表明了这些过程可能的实验特征。这些水中离子 - N₂O₄反应模型的结果揭示了氮氧化物与海水反应的分子层面机制。
