Liu Yiqiang, Liu Lijie, Fu Yanlin, Jiang Haotian, Wu Hao, Liu Yue, Lu Xiaoxiao, Zhou Xiaohu, Li Hongwei, Skodje Rex T, Wang Xingan, Fu Bina, Dong Wenrui, Zhang Dong H, Yang Xueming
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
School of Materials Science and Engineering, Anyang Institute of Technology, Anyang, China.
Nat Chem. 2025 Jun;17(6):897-903. doi: 10.1038/s41557-025-01798-9. Epub 2025 Apr 16.
Criegee intermediates are highly reactive species that play a pivotal role in the chemistry of the atmosphere, substantially impacting global climate and air quality. They are formed through the reaction of ozone with alkenes and considerably influence the formation of hydroxyl radicals and aerosols through their unimolecular decomposition and their reaction with key atmospheric components, respectively. However, their interaction with water vapour, a major atmospheric component, remains inadequately characterized. Here, using both time-dependent laser-induced fluorescence experiments and full-dimensional dynamics calculations, we investigate the reaction of syn-CHCHOO, a prevalent Criegee intermediate, with water vapour. Our results reveal a much higher reaction rate than previously estimated, challenging the conventional notion that unimolecular decomposition dominates syn-CHCHOO removal. Notably, we uncover a complex mechanism involving a roaming process that enhances reactivity. Our findings necessitate a revised assessment of reactions involving syn-mono- and di-substituted Criegee intermediates with water, which are crucial for accurately estimating the OH budget derived from these intermediates.
克里吉中间体是高活性物种，在大气化学中起着关键作用，对全球气候和空气质量有重大影响。它们通过臭氧与烯烃的反应形成，并分别通过单分子分解及其与关键大气成分的反应，对羟基自由基和气溶胶的形成产生显著影响。然而，它们与大气主要成分水蒸气的相互作用仍未得到充分表征。在这里，我们使用时间分辨激光诱导荧光实验和全维动力学计算，研究了常见的克里吉中间体顺式-CHCHOO与水蒸气的反应。我们的结果显示反应速率比先前估计的要高得多，这对单分子分解主导顺式-CHCHOO去除的传统观念提出了挑战。值得注意的是，我们发现了一种涉及漫游过程的复杂机制，该机制增强了反应活性。我们的研究结果需要对涉及顺式单取代和二取代克里吉中间体与水的反应进行修订评估，这对于准确估计源自这些中间体的OH收支至关重要。
