Synthesis and Coherent Vibrational Laser Spectroscopy of Putative Molecular Constituents in Secondary Organic Aerosol Particles

美国国家科学基金会化学部的环境化学科学项目支持来自西北大学的Regan J. Thomson和Franz M. Geiger教授的研究，他们将致力于开发新的化学、光谱和物理测量工具，以进一步了解有机气溶胶颗粒的化学成分。对二级有机气溶胶（SOA）粒子进行化学分析的研究，将有助于进一步了解与气候科学有关的预测云特性的重要参数。这些特性属于气候系统中最不为人所知的大气过程。本项目将结合合成有机化学和相干振动光谱学方面的专业知识进行以下工作：合成蒎烯、蒈烯和异戊二烯衍生的有机模型化合物，以理解和预测SOA颗粒的形成、性质和命运；2. 使用相干振动光谱对被认为存在于SOA颗粒内部和表面的分子成分进行首次明确的结构确认；, 3。将结果与在芬兰南部、亚马逊盆地中部和哈佛环境商会收集的SOA颗粒进行比较。除了通过西北大学的科学参与研究所将拟议的研究活动与学生和初级研究人员的有意义的参与相结合之外，该项目还将弥合目前限制SOA粒子形成的分子理解的重要知识差距。要合成的物种的同位素编辑将允许确定萜类及其衍生物的振动光谱，这对于这些迷人的化合物的基础理论和实验光谱研究是重要的。此外，该项目将向科学界提供以前没有合成和分析过的纯形式的化合物。

The Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation supports the research of Professors Regan J. Thomson and Franz M. Geiger both from Northwestern University who will focus on developing new chemical, spectroscopic, and physical measurement tools to further our understanding of the chemical composition of organic aerosol particles. Research enabling the chemical analysis of secondary organic aerosol (SOA) particles will enable subsequent understanding of parameters important in predicting cloud properties related to climate science. These properties rank among the least understood atmospheric processes in the climate system. This project will combine expertise in synthetic organic chemistry and coherent vibrational spectroscopy to do the following: 1. Synthesize pinene-, carene-, and isoprene-derived organic model compounds necessary for understanding and predicting the formation, properties, and fate of SOA particles; 2. Perform the first definitive structural confirmation of the molecular constituents that are thought to be present within and on SOA particles using coherent vibrational spectroscopy; and, 3. Benchmark the results to those obtained from SOA particles collected in Southern Finland, the central Amazon Basin, and the Harvard Environmental Chamber. In addition to integrating the proposed research activities with meaningful involvement of students and junior investigators via the Science Engagement Institute at Northwestern University, this project will bridge important knowledge gaps that currently curtail the molecular understanding of SOA particle formation. Isotope editing of the species to be synthesized will allow for the definite assignment of vibrational spectra of terpenes and their derivatives, which is important for fundamental theoretical and experimental spectroscopic studies of these fascinating compounds. In addition, the project will make available to the scientific community chemical compounds in pure form that have not previously been synthesized and analyzed.