Modeling Ozone Mass-Independent Fractionation (MIF) in Gas Phase and on Surfaces

该项目将研究导致平流层臭氧在氧的重同位素（17O和18O）中富集的质量无关分馏（MIF）效应。处理这种臭氧形成反应的理论将进一步发展，使用混合量子/经典方法来表征碰撞能量传递，而不使用降维近似。将研究几种常压浴气作为反应猝灭剂的使用。臭氧形成反应中氧的MIF已被证明在使用非常有效的分子猝灭剂（如SF6）时消失。这个项目的重点将是从解析模型转向动力学的主方程处理。该项目还将包括首次对表面臭氧形成进行量子动态计算。臭氧的质量无关分馏（MIF）对我们了解臭氧在大气中的化学性质、产生、寿命和损失以及臭氧对全球气候变化的影响具有重要意义。在进一步阐明O3的MIF方面取得的进展将为理解其他分子（如平流层CO2、N2O和CO）的MIF提供关键。大气CO2的同位素组成通常用于确定其来源，进一步表征CO2的MIF将有助于增加对全球碳收支的了解。

This project will investigate the mass-independent fractionation (MIF) effect that leads to enrichment of stratospheric ozone in heavy isotopes of oxygen (17O and 18O). The theory for treating this ozone forming reaction will be further developed using a mixed quantum/classical method to characterize the collisional energy transfer without using reduced-dimension approximations. The use of several atmospheric bath gases will be studied as quenchers for the reaction. The MIF of oxygen in the ozone-forming reaction has been shown to disappear when a very efficient molecular quencher, such as SF6, is used. The emphasis of the project will be on moving from the analytic model to a master-equation treatment of the kinetics. The project will also include the first-ever quantum dynamic calculations for the formation of ozone on surfaces.The mass-independent fractionation (MIF) of O3 has a significant impact on our understanding of the ozone's chemistry, production, lifetime and loss in the atmosphere, and the effect ozone has on global climate change. The advances made in further elucidating the MIF of O3 will provide the key to understanding the MIF for several other molecules, such as stratospheric CO2, N2O and CO. The isotopic composition of atmospheric CO2 is often used to identify its sources and further characterization of the MIF of CO2 will lead to an increased understanding of the global carbon budget.