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.
