Heterogeneous Oxidations of Chemically Diverse Organic Species Relevant to Tropospheric Aerosol Chemistry

该奖项是根据2009年《美国复苏和再投资法》(公法111-5)资助的。了解作为大气气溶胶一部分的有机化合物的化学对于评估气溶胶对气候和大气化学成分的影响至关重要。考虑到丰富的有机C=C双键氧化化学，以及大气中重要有机化合物中丰富的立体中心，立体化学可能在对流层化学过程中发挥重要作用，包括气溶胶表面的非均相反应。然而，令人惊讶的是，人们对大气立体化学知之甚少。该项目开始填补这一空白，应用非线性光学光谱，特别是二次谐波产生(SHG)和振动和频率产生(VSFG)来研究臭氧与表面活性、对流层相关的手性有机化合物的相互作用，因为它们不仅产生具有表面和分子特异性的重要光谱、结构和热力学信息，而且还产生获得可靠气候变化模型至关重要的动力学参数。实时动力学测量与表面光谱研究相结合，可以阐明非均相有机氧化反应机理。除了在环境污染背景下扩大对现实世界非均相化学的基本理解外，该项目的结果还使自然界中发现的界面现象的现有理论和机理框架取得了进展。这反过来又推进了一般管理多相化学的基本过程的分子水平的概念，并有助于提高预测人类活动对环境的影响的可靠性。通过直接和间接地与学生和政策制定者互动，综合研究、教育和公众宣传活动是向公众传播科学成果的强大工具。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Understanding the chemistry of organic compounds that are part of atmospheric aerosols is crucial for assessing the impact that aerosols have on climate and the chemical composition of the atmosphere. Given the rich, well documented organic C=C double bond oxidation chemistry, and given the abundance of stereocenters in atmospherically important organic compounds, stereochemistry could play an important role in tropospheric chemical processing, including heterogeneous reactions on aerosol surfaces. However, surprisingly little is known about atmospheric stereochemistry. This project begins to fill this void by applying nonlinear optical spectroscopies, specifically second harmonic generation (SHG) and vibrational sum frequency generation (VSFG) to study the interaction of ozone with surface-active, tropospherically relevant chiral organic compounds, as they yield not only important spectroscopic, structural, and thermodynamic information with surface and molecular specificity, but also the kinetic parameters that are vitally needed for obtaining reliable climate change models. Real-time kinetic measurements, combined with surface spectroscopic studies, allow elucidation of heterogeneous organic oxidation reaction mechanisms.In addition to expanding the fundamental understanding of real-world heterogeneous chemistry in the context of environmental contamination the results of this project also enable advances in existing theoretical and mechanistic frameworks for interfacial phenomena found in nature. This, in turn, advances molecular-level concepts of the fundamental processes governing heterogeneous chemistry in general and helps improve the reliability of predicting the impacts of human activities on the environment. By directly and indirectly interacting with students and policy makers, the integrated research, education, and public outreach activities are powerful tools for communicating the scientific outcomes to the general public.