Dynamics of Ion-Radical Collisions: Imaging Studies

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In this project supported by the Chemical Structure, Dynamics and Mechanisms Program and the Chemical Measurement and Imaging Program of the Division of Chemistry, Professor James Farrar of the University of Rochester and his research group will explore the collisions of free radicals and atomic or molecular ions. By employing a pulsed supersonic source of free radicals such as CH3 and C3H5, and an electron impact or discharge source of low energy cations such as N2+, N+, C+, Si+, and S+, and anions such as O-, O2-, and OH-, velocity space imaging methods will be used to detect the products of the reactions, yielding differential cross sections in kinetic energy and angle. Of particular interest are the bond formation reactions that yield C-C, C-O, C-N, N-O, S-C, and Si-C bonds. For anionic reactions, free electrons produced by associative detachment will also be detected. The experiments will represent the first dynamical studies of the reactions of low energy ions with free radicals and will address the serious deficiencies of models for electrical discharges and the chemistry of planetary atmospheres that do not include ion-radical reactions.In addition to characterizing the dynamics of the aforementioned chemical systems, this research will provide a deeper understanding of reactivity patterns and a molecular understanding of the chemistry that takes place in electrical discharges such as those involved in reactive ion etching, and in atmospheric and extraterrestrial chemistry. The instrumental technique development may have impacts in various subdisciplines of chemistry, including mass spectrometry and ion imaging. The graduate and undergraduate students and post-doctoral associates involved in this research will contribute to the national scientific and economic infrastructure through the development of new measurement technologies, new high value-added products, and the further training of scientific personnel.