Ion-Molecule Reactions in Gas-Phase Clusters and Buffer Gas Flows

Hendrix学院的David Hales教授将在化学学部物理化学项目中研究气相离子-分子反应对离子内能的依赖关系。为了完成这项任务，将使用两种不同的实验技术。在第一种方法中，将寻找发生在电离分子团内的反应的证据，这些反应是在超音速膨胀中产生的，并被电子撞击电离。簇中离子的碰撞弛豫涉及潜在的反应性相互作用。第二种技术涉及在气体混合物膨胀到真空之前在高压流管内放电电离。在膨胀前的环境中，离子与缓冲气体发生多次热化碰撞，每次碰撞都与一个潜在的反应分子发生碰撞。用飞行时间质谱仪对流出管的离子进行探测。将根据反应发生的不同环境来分析两种技术之间结果的差异。本研究涉及本科生的参与。离子分子化学是当代反应化学研究的热点之一。这项研究将有助于更好地理解在不同气相环境中发生的反应过程，其结果将用于大气化学等应用。本研究将在一所本科院校进行，涉及本科生。

In this project in the Physical Chemistry program of the Chemistry Division, Prof. David Hales of Hendrix College will study the dependence of of gas-phase ion-molecule reactions on ion internal energy. To accomplish this task two different experimental techniques will be used. In the first, evidence will be sought for reactions which take place within ionized clusters of molecules produced in a supersonic expansion and ionized by electron impact. Collisional relaxation of an ion in a cluster involves potentially reactive interactions. The second technique involves discharge ionization within a high pressure flow tube prior to expansion of the gas mixture into a vacuum. In the pre-expansion environment the ions undergo many thermalizing collisions with the buffer gas for each collison with a potenntially reactive molecule. The ions which exit the flow tube are probed with a time of flight mass spectrometer. Differences in the results between the two techniques will be analyzed in terms of the different environments in which the reactions take place. This research involves the participation of undergraduate students. Ion-molecule chemistry is one of the intensely pursued areas of contemporary reaction chemistry. This research will contribute to a better understanding of the reaction processes that occur in different gas phase environments, and the results will be of use in applications such as atmospheric chemistry and others. This research will be conducted in an undergraduate college and will involve undergraduate students.