Theoretical study of the formation and nucleation mechanism of highly oxygenated multi-functional organic compounds produced by alpha-pinene
Theoretical study of the formation and nucleation mechanism of highly oxygenated multi-functional organic compounds produced by alpha-pinene
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α-蒎烯高含氧多功能有机化合物形成及成核机理的理论研究
DOI：
10.1016/j.scitotenv.2021.146422
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发表时间：
2021
影响因子：
9.8
通讯作者：
Wenxing Wang
中科院分区：
文献类型：
--
作者：
Xiangli Shi;Guoxuanzi Huang;Dehui Yang;Qingzhu Zhang;Wansong Zong;Jiemin Cheng;Xiao Sui;Fanghui Yuan;Wenxing Wang
近年来，由α-蒎烯光化学反应产生的高含氧有机分子（HOM）被认为是重要的生物颗粒前体。然而，HOMs的具体反应仍然在很大程度上是未知的，特别是在纳米尺度下相应的形成和成核机制。本研究通过量子化学计算和分子动力学模拟来探索α-蒎烯臭氧分解和自氧化形成HOM单体/二聚体的机制。此外，我们研究了具有不同氧碳比（O/C）和官能团的HOM参与中性和离子诱导成核的机制。结果表明，水、硫酸和离子对HOMs的形成几乎没有影响。在离子诱导成核中，HOM可以主导初始成核步骤;然而，在中性成核中，HOM更可能参与生长阶段。此外，HOM的成核能力与O/C比和官能团类型有关。目前的计算提供了有价值的洞察在低硫酸浓度下的纯有机颗粒的形成机理。
In recent years, highly oxygenated organic molecules (HOMs) derived from photochemical reactions of α-pinene, the most abundant monoterpene, have been considered as important precursors of biogenic particles. However, the specific reactions of HOMs remain largely unknown, especially the corresponding formation and nucleation mechanism in the nanoscale. In this study, we implemented quantum chemical calculations and molecular dynamics (MD) simulations to explore the mechanism of the formation of HOM monomers/dimers by ozonolysis and autoxidation of α-pinene. Furthermore, we investigated the mechanisms of HOMs with different oxygen-to‑carbon (O/C) ratios and functional groups participating in neutral and ion-induced nucleation. The results show that the formation of HOMs is hardly affected by water, sulfuric acid and ions. In the ion-induced nucleation, HOM can dominate the initial nucleation steps; however, in the neutral nucleation, HOMs are more likely to participate in the growth stage. In addition, the nucleation ability of HOM has a bearing on the O/C ratio and the types of the functional groups. The current calculations provide valuable insight into the formation mechanism of the pure organic particles at low sulfuric acid concentrations.