Chirality in Aerosol Chemistry

化学系的环境化学科学(ECS)计划、大气和地球空间科学系的大气化学计划以及国际科学与工程办公室(OISE)将支持西北大学的Franz Geiger教授和哈佛大学的Scot Martin教授的合作研究计划。盖格教授、马丁教授和他们的学生将结合实验室和现场实验来检验这一假说，就像一个人的双手可以用弦来产生手性弦图一样，手性生物挥发性有机化合物的氧化可以在大气颗粒物中产生手性有机物质，对进一步的化学反应和物理性质产生重要影响。这两个研究小组将使用一个环境舱，在受控的对流层相关条件下，从手性生物成因挥发性有机化合物的混合物中合成和分析手性二次有机材料。利用非线性光学化学成像和非线性光学激光光谱，将研究新形成的次生有机材料的气候相关性质，作为气相中立体异构体混合物的函数，并与有机材料的化学成分和手性相关联。实验室模型研究将以亚马逊盆地中部收集的有机气溶胶颗粒的化学成分、大小分布和来源为基准，该盆地以原始条件为特征，人为投入最少。研究手性气溶胶化学有可能从根本上发现新的气溶胶过程，这可能有助于改进对气候系统辐射强迫的预测。手性大气立体化学也可以朝着手性标记发展，以区分燃烧化石燃料和燃烧森林。这可能会改变目前生物排放与人为排放来源解析的方法，这些方法通常基于昂贵的同位素分析。该项目将为希望在具有重大社会意义的领域从事专业科学事业的学生，包括代表人数不足的群体成员提供极好的培训机会。

The Environmental Chemical Sciences (ECS) program of the Division of Chemistry, the Atmospheric Chemistry program of the Division of Atmospheric and Geospace Sciences and the Office of International Science and Engineering (OISE) will support the collaborative research program of Prof. Franz Geiger of Northwestern University and Prof. Scot Martin of Harvard University. Professor Geiger, Professor Martin, and their students will combine laboratory and field experiments to test the hypothesis that just like the two hands of one person can use string to produce chiral string figures, the oxidation of chiral biogenic volatile organic compounds can produce chiral organic material in atmospheric particles, with important effects on further chemical reactivity and physical properties. The two research groups will use an environmental chamber to synthesize and analyze chiral secondary organic material from mixes of chiral biogenic volatile organic compounds under well-controlled tropospherically relevant conditions. Climate-related properties of the newly formed secondary organic material will be investigated as a function of the stereoisomeric mix in the gas phase and correlated with the chemical composition and chirality of the organic material using nonlinear optical chemical imaging and nonlinear optical laser spectroscopy. Laboratory model studies will be benchmarked against chemical composition, size distribution, and origin of organic aerosol particles collected in the central Amazon Basin, which features pristine conditions with minimal anthropogenic input. Studying chiral aerosol chemistry has the potential to allow for the discovery of fundamentally new aerosol processes, which could help improve the prediction of radiative forcing of the climate system. Chiral atmospheric stereochemistry could also be developed towards a chiral marker to distinguish, for instance, burning fossil fuels from burning forests. This could potentially transform current methods for source apportionment of biogenic vs. anthropogenic emissions, which are commonly based on costly isotope analysis. The project will provide excellent training opportunities to students, including to members of under-represented groups, who wish to pursue a professional scientific career in an area of great societal importance.