Free Radical Kinetics

Research in this domain is built upon the scientific objectives set by three issues: toxicity in urban-regional environments, the coupling of chemistry, radiation and dynamics in the climate system, and ozone loss in the lower stratosphere over mid latitudes of the Northern Hemisphere. Central to all of these issues is the kinetics of radical-molecule systems involving hydrogen, oxygen, sulfur, chlorine, bromine and carbon. We address a series of laboratory investigations that seek to investigate a subset of what we believe are the most important questions that have emerged from a combination of atmospheric observations, modeling of atmospheric processes, and the societal demands noted above. This implies laboratory studies of the rates and mechanisms of atmospheric reactions over broad ranges of temperature (150-400 K) and pressure (10-500 hPA). Specifically, we propose to study the individual steps of the radical-initiated oxidation of organic compounds (involving alkyl radicals, alkoxy radicals, alkylperoxy radicals, alkyl nitrates, etc.), the importance of weakly-bound complexes on reaction rates and mechanisms, and the low-temperature kinetics of halogen radical and HO_x–NO_x reactions that underpin ozone loss calculations at low temperatures.