Gas Phase Ion Chemistry and Thermochemistry

实验物理化学项目支持科罗拉多大学博尔德分校Veronica Bierbaum教授继续研究气相离子-分子反应的动力学、机理和热化学。Bierbaum博士将在以下领域开展研究：1)研究氯甲烷的对称SN2反应作为压力、缓冲气体和同位素取代的函数，以及SN2在气相中性氮下的反应活性；离子热化学与大气相关系统的实验和计算研究。此外，她还将从事两个新的项目：3)离子与氮、氧原子的反应研究；4)生物源排放物的化学电离检测。PI将采用串联流动余光选择离子流漂移管与三重四极探测器相结合来进行反应和监测产物。本研究项目的实验结果将有助于我们对反应动力学、机理和热化学的基本认识，并提供有价值的理论比较。许多热化学数据与重要的燃烧和大气过程有关。生物源排放的特征解决了大气化学中的一个关键问题：地球对流层中高浓度含氧碳氢化合物的来源目前尚不清楚；然而，它们对大气化学的影响是显著的。

The Experimental Physical Chemistry Program supports Prof. Veronica Bierbaum of the University of Colorado-Boulder in her continuing studies of the kinetics, mechanisms and thermochemistry of gas phase ion-molecule reactions. Dr. Bierbaum will carry out research in the following areas: 1) the study of symmetric SN2 reactions of methyl chloride as a function of pressure, buffer gas and isotope substitution, and SN2 reactivity at neutral nitrogen in the gas phase; and 2) experimental and computational studies of ion thermochemistry to systems of atmospheric relevance. In addition, she will pursue two new projects: 3) the study of reactions of ions with nitrogen and oxygen atoms; and 4) chemical ionization detection of biogenic emissions. The PI will employ a tandem flowing afterglow-selected ion flow-drift tube coupled with a triple quadrupole detector to carry out the reactions and monitor products. The experimental results from this research program will contribute to our fundamental understanding of reaction kinetics, mechanism, and thermochemistry, as well as provide valuable comparison with theory. Much of the thermochemical data has relevance to important combustion and atmospheric processes. The characterization of biogenic emissions addresses a critical problem in atmospheric chemistry: the sources of high concentrations of oxygenated hydrocarbons in the earth's troposphere are not currently understood; however, their impact on atmospheric chemistry is significant.