The influence of hydrogen bonding on the atmospheric chemistry of peroxy and carboxylic acids

在这个由化学系化学结构、动力学和机制计划和大气和地球空间科学系大气化学计划联合资助的项目中，加州大学圣地亚哥分校的阿米塔巴·辛哈教授研究了氢键在影响大气中重要的含氧有机分子化学中所起的作用。通过人为和生物活动释放到大气中的有机分子发生反应，形成氧化产物。这些氧化产物的极性增强，导致它们能够通过氢键相互作用。尽管氢键很弱，但它无处不在。研究氢键对含氧有机物化学的微妙影响有助于我们更好地理解控制城市空气质量和大气辐射平衡的大气过程。此外，研究还允许对研究生和本科生进行培训和教育。该项目还为高中生和代表不足群体的学生提供了接触大学研究的机会。在这项工作中，使用振动泛音激发结合激光诱导荧光检测、动力学分析和计算化学来研究氢键对几种含氧有机分子化学的影响。在第一阶段的工作中，我们探讨了分子内氢键对过氧酸的振动光化学和单分子解离动力学的影响。在第二阶段的研究中，研究了羧酸通过分子间氢键促进氢原子转移反应的能力。有机酸在大气中普遍存在，因为它们是碳氢化合物氧化的副产品。它们催化氢原子转移反应的能力使它们成为包括气溶胶增长在内的各种大气过程的重要贡献者。

In this project funded jointly by the Chemical Structure, Dynamics and Mechanisms A Program of the Division of Chemistry and the Atmospheric Chemistry Program in the Division of Atmospheric and Geospace Sciences, Professor Amitabha Sinha of University of California San Diego investigates the role played by hydrogen bonding in influencing the chemistry of oxygenated organic molecules of atmospheric importance. Organic molecules released into the atmosphere through anthropogenic and biogenic activity undergo reactions that result in the formation of oxidized products. The enhanced polar character of these oxidized products results in their ability to interact through hydrogen bonding. Although weak, hydrogen bonds are pervasive. Investigating the subtle impact of hydrogen bonding on the chemistry of oxygenated organics contributes to improving our understanding of atmospheric processes that control urban air quality as well as atmospheric radiative balance. In addition, the research permits the training and education of students at the graduate and undergraduate. The project also provides opportunities for high school students and students from underrepresented groups to be exposed to university research.In this work, vibrational overtone excitation combined with laser induced fluorescence detection, kinetic analysis, and computational chemistry is used to investigate the impact of hydrogen bonding on the chemistry of several oxygenated organic molecules. In the first phase of the work the impact of intramolecular hydrogen bonding on the vibrational photochemistry and unimolecular dissociation dynamics of peroxyacids is probed. In the second phase of the study the ability of carboxylic acids to promote hydrogen atom transfer reactions through intermolecular hydrogen bonding is investigated. Organic acids are ubiquitous in the atmosphere as they are byproducts of hydrocarbon oxidation. Their ability to catalyze hydrogen atom transfer reactions makes them an important contributor to various atmospheric processes including aerosol growth.