In this project in the Experimental Physical Chemistry Program of the Chemistry Division, James Kinsey of Rice University will develop new picosecond laser techniques for studying reaction dynamics of excited electronic states. Particular attention will be paid to the Raman excitation profile, which arises from the small fraction of excited molecules which emit photons at some point during their decomposition. Theoretical analyses of these profiles provides a unique source of information about the earliest stages of photodecomposition. %%% Photochemical decompositions are among the most fundamental and important of chemical processes. For example, a detailed elucidation of how sunlight leads to ozone decomposition is essential if we hope to alter the environmental consequences of ozone layer depletion. The early stages of such photochemical reactions are very hard to study in the laboratory since they are over in less time than light takes to travel 0.001 inches. Prof. Kinsey's studies of photochemical decomposition of ozone and other molecules will provide powerful new tools for gaining insight into reactions on this ultrafast timescale.