In the project in the Experimental Physical Chemistry Program, Donald Setser of Kansas State University will study state-resolved dynamics and kinetics of phase species important in combustion and atmospheric chemistry. Various spectroscopic methods will be used to prepare reactants and observe product state distributions. Infrared chemiluminescence will be used to study products from atom-radical and radical-radical reactions, identify mechanisms, and determine overall rate constants. Electronic emission and laser induced fluorescence will be used to study the mechanism and state distributions of rare gas halide molecules produced by two-photon laser assisted reactions. These studies will compare the state distributions of products resulting from collisions in dilute gas mixtures with those obtained from reactions within a prepared van der Waals molecule. The results of these investigations will be interpreted in terms of dynamical models which have been developed for certain types of gas phase reactions and the insights obtained will be used to understand more complex reactive systems. Radicals are highly reactive, usually unstable molecules which are present in high concentration in energetic chemical reactors such as combustion systems. Reactions of radicals are also important in the mechanisms responsible for the depletion of the ozone layer and global warming. Professor Setser's investigations will provide information about the elementary reactions involved in these mechanisms, and the nature and energy content of the species produced by these reactions.