Kinetics of Gas Phase Reactions of Atoms and Radicals

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Atmospheric Chemistry:    Atomic bromine and atomic chlorine are implicated in a range of chemical processes that take place in the atmosphere, one of the most publicized ones being ozone depletion.  In order to assist in the quantitative understanding of such processes, we are engaged in a research program that seeks to measure parameters that could help in determining the relative importance of reactions of organic compounds with atomic bromine and chlorine in controlling the concentrations of these atomic species in the atmosphere.  This has implications for predicting related atmospheric phenomena such as ozone depletion events.    Our experiments allow us to selectively produce the reactions of interest under simulated atmospheric conditions in a 70 Litre reaction vessel.  The atomic bromine and chlorine are produced by using light with a spectrum similar to that of the sun to break apart molecular bromine and molecular chlorine.  The extent of reaction with the organic compounds is determined by chemical analysis of the mixture in the reaction vessel and this information allows us to characterize the reactions of a wide range of substances.  The results obtained permit predictions of reactivity based on molecular structure.Generation and Reactivity of Soot:    Our research in this area is focused on the high temperature reactions of hydrocarbons that take place during petroleum refining and during combustion of fossil fuels.  The work requires chemical analysis of the product yields under high temperature reaction conditions combined with computer modeling of the very large set of chemical reactions required to describe the overall chemical process being studied.  This work is expected to aid in identifying new technologies for using fossil fuels.  In this way, the research will contribute to the development of processes for using natural gas and petroleum in more environmentally friendly ways.  The results will also provide information on the role of soot particles in atmospheric chemistry.