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，但涉及这种关键且无处不在的光化学臭氧前体的氧化途径在机制上仍然受到相当少的限制。该建议是在首席研究员之前的实验室和理论研究工作的基础上提出的，这些研究是在对流层典型的低活性和高活性氧化氮（NOx）条件下，异戊二烯的氧化速率和硝酸盐产量随温度和压力的变化而变化，并选择了烯烃模型系统。该项目的另一个方面将涉及挖掘来自过去几个项目的现有环境数据集，这些数据集在nox限制的光化学制度下获得了现场测量，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制准确性。这项研究的结果将为对气候具有重要意义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式如何处理这些系统的一些不确定性，并在这样做时导致更好地理解有助于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的指导下获得专业的研究培训和经验。暑期本科生也将参与这项研究，通过本科生研究经验（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.