RUI: Computational Modeling of Hydroxyl Radical and Carboxylic Acid Formation in the Atmosphere

该项目由国家科学基金会化学部环境化学科学计划资助。教授基思T. Macalester学院的Kuwata教授和Stacey A.威斯康星大学里弗福尔斯分校的斯托弗雷根和他们的本科研究生正在开发更精确和详细的大气化学反应理论模型。该项目最重要的广泛影响是Macalester和河流瀑布本科生接受的培训，以进行大气化学的重要研究，这反过来又使他们能够在STEM领域进行高级研究。这项研究也有助于中西部大学生计算化学联盟（MU3C）的智力活力，Kuwata教授和Stoffregen教授都属于该联盟。他们的学生将在每年夏天的MU3C会议和每年冬天的在线MU3C会议上介绍他们的研究项目。MU3C会员资格使PI及其学生有机会与其他九个主要本科院校的计算化学教师和学生进行交流，每年两次。该项目的重点是澄清烃氧化反应中的中间体对自由基和羧酸浓度的影响。一个感兴趣的中间体是乙烯基过氧化氢（VHP）形成的大气烯烃臭氧分解。目前的实验和理论研究表明，VHP进行均裂形成OH的趋势与原始烯烃的大小和结构以及大气条件有关。理解这些变化需要更多的创造力，可能的VHP化学反应和量子化学方法的应用，可以准确地模拟分子与大量的静态电子相关。 这些模型提供了新的机制的见解，通过对瞬态物种，不能直接表征实验的预测大气过程。同时，这些模型也被用来预测实验已知的量，如稳定的大气物种的浓度。理论和实验之间的比较既验证了理论预测，又推动了新理论方法的发展和应用。

This project is funded by the Environmental Chemical Sciences Program in the Division of Chemistry at the National Science Foundation. Professors Keith T. Kuwata of Macalester College and Professor Stacey A. Stoffregen of the University of Wisconsin-River Falls and their undergraduate research students are developing more accurate and detailed theoretical models of chemical reactions in the atmosphere. The most significant broader impact of the project is the training that Macalester and River Falls undergraduates receive to conduct significant research in atmospheric chemistry, which in turn equips them to pursue advanced study in STEM fields. This research also contributes to the intellectual vitality of the Midwest Undergraduate Computational Chemistry Consortium (MU3C), to which both Professor Kuwata and Professor Stoffregen belong. Their students will make presentations on their research projects at the in-person MU3C conference every summer and the on-line MU3C conference every winter. MU3C membership gives the PIs and their students opportunities to interact with fellow computational chemistry faculty and students at nine other primarily undergraduate institutions at conferences twice a year.The project focuses on clarifying the impacts that intermediates in hydrocarbon oxidation reactions have on free radical and carboxylic acid concentrations. One intermediate of interest is the vinyl hydroperoxide (VHP) formed in atmospheric alkene ozonolysis. Current experimental and theoretical studies suggest that the tendency of the VHP to undergo homolysis to form OH varies with both the size and structure of the original alkene and with atmospheric conditions. Understanding these variations requires more creativity about possible VHP chemical reactions and the application of quantum chemical methodology that can accurately model molecules with substantial static electron correlation. Such models provide new mechanistic insights about atmospheric processes by making predictions about transient species that cannot be directly characterized experimentally. At the same time, these models are also used to predict experimentally known quantities such as the concentrations of stable atmospheric species. Comparisons between theory and experiment both validate theoretical predictions and drive the development and application of new theoretical methods.