Experimental and Theoretical Investigations of the Oxidation of Isoprene and Other Select Model Alkenes

尽管持续的研究活动旨在了解异戊二烯的行为，但涉及这种关键的和普遍存在的光化学臭氧前体的氧化途径在机械上仍然受到相当差的限制。这项建议是根据首席研究人员之前在实验室的工作和对异戊二烯和部分烯烃模型体系在环境对流层典型的低活性和高活性氧化氮(NOx)条件下与温度和压力相关的氧化速率和硝酸盐产率的理论研究得出的。该项目的另一个方面将涉及从过去的几个项目中挖掘现有的环境数据集，这些项目在NOx受限的光化学制度下获得现场测量结果，并使用化学坐标分析方法来评估这些先前发现的一致性和机械准确性。这项研究的结果将为气候重要的烯烃化学和光化学循环的机制提供实质性的新见解，调和或至少限制目前模型如何处理这些系统的一些不确定因素，并通过这样做有助于更好地理解促成对流层臭氧形成和积累的因素。这项工作的更广泛的教育影响包括支持两名研究生，他们将在PI的指导下获得专业研究培训和经验。暑期本科生也将参与这项研究，通过本科生研究体验(REU)活动进行解释性数据分析。

Despite continued research activity aimed at understanding isoprene behavior, oxidative pathways involving this critical and ubiquitous photochemical ozone precursor remain rather poorly constrained mechanistically. This proposal follows on from the Principal Investigator's previous work in laboratory and theoretical investigations of the temperature- and pressure-dependant oxidation rates and nitrate yields of isoprene and select alkene model systems under low- and high- reactive oxidized nitrogen (NOx) conditions typical of the ambient troposphere. Another aspect of this project will involve mining existing ambient data sets from several past programs that acquired field measurements under NOx-limited photochemical regimes and using a chemical coordinate analysis approach to assess consistency and mechanistic accuracy in these previous findings. Results from this study will provide substantial new insights into the mechanisms of climatically important alkene chemistry and photochemical cycling, reconcile or at least constrain some current uncertainties in how models treat these systems, and in doing so lead to a better understanding of factors contributing to the formation and accumulation of tropospheric ozone. The broader educational impacts of this work include support for two graduate students who will gain professional research training and experience under the mentorship of the PI. Summer undergraduate students will also be involved in this research performing interpretive data analyses through a Research Experiences for Undergraduates (REU) activity.