作为过氧自由基化学研究的重要分支，羰基氧化物即Criegee中间体(CI)不仅能够解离产生•OH，而且可以作为强氧化剂与大气分子反应形成酸雨和二次污染物。明确CI在大气中的微观反应通道对估算大气物种的寿命和大气氧化能力以及揭示大气复合污染过程具有重要的科学意义。目前关于CI的理论研究较多，然而受限于CI在室温下的瞬态特性与实验合成方法的匮乏，使得大量CI尚未被光谱表征；此外，CI的气相反应非常复杂，反应过程中的关键中间体难以直接被光谱探测，导致对相应微观反应机理的认识比较欠缺。.本课题拟结合低温微量合成与反射式基质隔离原位光谱探测技术，针对目前被理论预测的CI如卤素取代的XCHOO和氰基取代衍生物NCCHOO，开展光谱探测与重要基元反应的实验研究；借助基质掺杂与光诱导，在极低温惰性基质中捕获CI与典型小分子如SO2和H2O反应过程中的瞬态中间体，结合高精度量子化学计算完整解析微观反应历程。

Carbonyl oxides, also known as Criegee intermediates, can dissociate to produce •OH radical or react with atmospheric molecules to form sulfuric acid and secondary pollutants. Elucidating reaction channels of Criegee intermediates is necessary for estimating the lifetimes of atmospheric species and atmospheric oxidation capacity and understanding the formation of combined pollution. Due to the short-lived nature at room temperature and, particularly, the lack of experimental synthesis method, a large number of Criegee intermediates have not been characterized. Additionally, the gas-phase reactions between CI and atmospheric molecules are very complicated and the key intermediates in the process can hardly be detected, which leads to a lack of understanding of the reaction mechanism although there are extensive theoretical predications..This project will combine the low-temperature microsynthesis of metastable compounds with the matrix-isolation spectroscopic detection to explore the Criegee intermediates and their significant reactions which have been predicted by theory, for example, the halogen-substituted derivatives XCHOO and cyano-substituted derivative NCCHOO. By matrix doping and light irradiation, the transient intermediates in the reactions between CI and typical molecules such as SO2 and H2O will be generated and captured in cryogenic matrices. The experimental studies in conjunction with quantum chemistry calculations will uncover the molecular and electronic level mechanisms.