Abstract Secondary organic aerosols (SOA) have significant effects on atmospheric chemistry, human health and climate forcing, but their formation mechanisms via Criegee chemistry are still poorly understood. Here we present a comprehensive theoretical investigation on the oligomerization reaction of stabilized Criegee intermediates (SCIs) with organic acid/peroxy radical by using ab initio quantum-chemical methodologies. Our results show that the ozonolysis of isoprene easily leads to a series of C3 and C4 stable CIs due to its larger exothermicity and spontaneity. The formed SCIs have two isomers: syn- and anti-, and anti- is more stable in energy than that of syn- by about 2–5 kcal mol−1. The barrier heights of oligomerization reactions are very sensitive to the size and structure of functional groups near the central carbon atom site, indicating they can be tuned by the substitutions. Reaction between SCIs and peroxy radical contributes significantly to the formation of oligomer which is the dominant component of SOA. However, the reaction between SCIs and organic acid plays an important role in aerosol nucleation in some regions where high SCI and low H2O concentrations occur such as in terrestrial equatorial area. Such knowledge should be useful for understanding the mechanism of SOA formation from alkenes ozonolysis and for developing atmospheric chemistry models.

中文翻译：

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criegee中间体与有机酸/过氧自由基的低聚反应对异戊二烯臭氧分解二次有机气溶胶形成的影响

摘要 二次有机气溶胶（SOA）对大气化学、人类健康和气候强迫有显着影响，但其通过 Criegee 化学形成的机制仍知之甚少。在这里，我们使用从头算量子化学方法对稳定的 Criegee 中间体 (SCIs) 与有机酸/过氧自由基的低聚反应进行了全面的理论研究。我们的结果表明，异戊二烯的臭氧分解由于其较大的放热性和自发性，很容易导致一系列 C3 和 C4 稳定 CI。形成的SCIs有两种异构体：syn-和anti-，anti-的能量比syn-更稳定约2-5 kcal mol-1。低聚反应的势垒高度对中心碳原子位点附近官能团的大小和结构非常敏感，表明它们可以通过替换进行调整。SCIs 和过氧自由基之间的反应显着促进了低聚物的形成，低聚物是 SOA 的主要成分。然而，在一些发生高 SCI 和低 H2O 浓度的地区，如陆地赤道地区，SCI 与有机酸之间的反应在气溶胶成核中起着重要作用。这些知识应该有助于理解烯烃臭氧分解形成 SOA 的机制和开发大气化学模型。SCIs 与有机酸之间的反应在一些发生高 SCI 和低 H2O 浓度的地区（例如陆地赤道地区）的气溶胶成核中起着重要作用。这些知识应该有助于理解烯烃臭氧分解形成 SOA 的机制和开发大气化学模型。SCIs 与有机酸之间的反应在一些发生高 SCI 和低 H2O 浓度的地区（例如陆地赤道地区）的气溶胶成核中起着重要作用。这些知识应该有助于理解烯烃臭氧分解形成 SOA 的机制和开发大气化学模型。