Experimental and Theoretical Studies of Fundamental and Photochemical Processes in Aqueous Environments

国家科学基金会化学部的环境化学科学计划支持科罗拉多大学博尔德分校的Veronica Vaida教授和Rex T.Skodje教授的研究，他们的团队合作进行实验/理论工作，重点研究有机分子在气相中发生在空气/水界面和小水合物团簇中的光化学反应。这些光化学反应可以在大气气溶胶的形成和化学演变中发挥重要作用，对人类健康和气候变化具有潜在的重要后果。这项拟议的研究的学术价值来自于解决阳光引发的、水介导的有机分子化学的基本科学方面。利用实验室和理论研究相结合的方法，这项工作的结果将是更好地理解在大气中重要的星系团和气溶胶表面发生的光化学反应的机制、动力学和速率。这项工作与其他工作的不同之处在于，它强调推导水环境中大气光化学的分子水平机制和定量模型。预计，对气溶胶和更一般的水环境中发生的光化学所涉及的基础化学有更多的了解。拟议工作的一个重要部分是使用法国CESAM仪器(实验多相大气模拟室)直接观测空气/水/有机气相混合物的光化学。在这个小室中进行的实验可以直接观察在强烈的紫外线/可见光辐射的影响下气溶胶的形成和混合物的化学演变。就更广泛的影响而言，提高模拟气候变化所涉及的大气过程的能力是社会的一个重要目标，可以影响公共政策。目前模型中的气溶胶处理是一个“薄弱环节”，需要给予极大的关注。拟议的气溶胶成核和化学演化中涉及的光化学机制的研究有可能通过纳入对二次有机气溶胶化学的更正确的处理来改进这些模型的性能。此外，拟议的跨学科、国际合作将促进学生和博士后研究员的交流，并促进不同机构之间在大气光化学基础科学方面的思想交流。拟议的研究方案通过暴露在协作和跨学科的研究环境中，促进研究生和本科生的招生、留住和教育发展，特别是来自代表性不足的群体。

The Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation supports the research of Professors Veronica Vaida and Rex T. Skodje both at the University Colorado at Boulder in a collaborative experimental/theoretical effort by their groups that is focused on the study the photochemical reactions of organic molecules occurring at air/water interfaces and in small hydrated clusters in the gas phase. These photochemical reactions can play an important role in the formation and chemical evolution of atmospheric aerosols with potential important consequences to human health and climate change. The intellectual merit in the proposed investigation stems from addressing the basic scientific aspects of sunlight-initiated, water-mediated chemistry of organic molecules. Using a combination of laboratory and theoretical studies, the outcome of the work will be an improved understanding of the mechanisms, dynamics, and rates of photochemical reactions occurring in clusters and on aerosol surfaces that are of importance in the atmosphere. What distinguishes this work from other efforts is the emphasis on deriving molecular-level mechanisms and quantitative models for atmospheric photochemistry in aqueous environments. It is anticipated that greater understanding of the fundamental chemistry involved in the photochemistry occurring in aerosols and more general aqueous environments. An important part of the proposed work is the direct observation of the photochemistry of air/water/organic gas phase mixtures using the French CESAM instrument (Experimental Multiphasic Atmospheric Simulation Chamber). Experiments conducted in this chamber permit the direct observation of aerosol formation and the chemical evolution of the mixture under the influence of intense UV/visible radiation.In terms of broader impacts, improving the ability to model atmospheric processes involved in climate change is an important goal for society and can impact public policy. The treatment of aerosols in current models is a "weak link" and requires significant attention. The proposed study of photochemical mechanisms involved in aerosol nucleation and chemical evolution has the potential to provide improved performance of these models by incorporating a more correct treatment of the chemistry of secondary organic aerosols. In addition, the interdisciplinary, international collaborations proposed will lead to the exchange of students and postdoctoral fellows, and promote cross-fertilization of ideas between different institutions in the basic science of atmospheric photochemistry. The proposed research program contributes to the recruitment, retention and educational development of graduate and undergraduate students, especially from under-represented groups, by exposure to a collaborative and interdisciplinary research environment.