Reactions of Hydroxyl Radicals and Ozone with Volatile Organic Compounds Within Gas Phase Clusters: Experiment and Theory

小行星9713381 羟基自由基（OH）与生物或人为来源的挥发性有机化合物（VOCs）的反应是对流层臭氧的主要来源。OH与VOC的反应也会导致有害酸性化合物的形成。VOCs与臭氧反应形成各种产物，包括高能双自由基和OH自由基，臭氧-烯烃反应可能是夜间OH的重要来源。 该项目解决了上述反应如何通过气溶胶颗粒（雾，雨，云滴等）的存在来介导。在这项研究中，它将确定如何气相化学变化，如果自由基反应发生在气相分子簇作为一个模型的更大的空气中的气溶胶颗粒。 布法罗大学小组在实验和理论上都有研究气相团簇内化学反应的经验。据观察，经常发生在集群中的化学是非常不同的，在气相中。在簇内溶剂化分子可以在足够长的时间尺度上稳定试剂或中间体以在簇内反应。在这些实验中，通过分子束膨胀制备含有硝酸、VOC、水和其他配体分子的气相簇。OH将通过硝酸或其他合适的前体的光解产生。将通过串联质谱法监测反应产物。理论计算将提供中间双自由基的能量和寿命的估计。

9713381 Garvey The reaction of hydroxyl radical (OH) with volatile organic compounds (VOCs) of biogenic or anthropogenic origin is a major source of tropospheric ozone. The reaction of OH with VOCs can also lead to the formation of harmful acidic compounds. VOCs react with ozone to form a variety of products, including energetic biradicals and OH radicals, and ozone-alkene reactions can be an important nighttime source of OH. This project addresses how the above reactions could be mediated by the presence of aerosol particles (fog, rain, cloud droplets, etc.). In this research, it will be determined how the gas phase chemistry changes if the radical reactions occur within a gas phase cluster of molecules as a model of much larger airborne aerosol particles. The University at Buffalo group has experience in studying chemical reactions within gas phase clusters both experimentally and theoretically. It was observed that frequently, the chemistry occurring in clusters is very different from that in the gas phase. Solvating molecules within the cluster can stabilize a reagent or intermediate on a time scale long enough to react within the cluster. In these experiments, gas phase clusters containing nitric acid, the VOC, water, and other ligand molecules will be prepared via molecular beam expansion. OH will be produced via photolysis of nitric acid or other suitable precursors. Reaction products will be monitored via tandem mass spectrometry. Theoretical calculations will provide estimates of the energetics and lifetimes of intermediate biradicals.