9304691 Chen In this project of the Physical Chemistry Program in the Chemistry Division, Prof. Y. Chen of the University of California at Berkeley will pursue a program of research to provide a systematic understanding of the interplay between intramolecular energy transfer and chemical reactions. To this end the new technique of femtosecond time-domain Transient Stimulated Emission Pumping (TSEP) spectroscopy invented by him will be applied to two model systems, ozone and methylnitrite to obtain real-time emission spectra during the photofragmentation of these species. %%% The details of chemical reaction and dissociation processes occur at pico- to femtosecond time scales and research in this field is at the forefront of contemporary physical chemistry. Among the questions posed by these processes is how the energy which excites a specific molecular vibrational state redistributes itself within the molecule to result in the dissociation of the molecule by the breaking of a specific chemical bond or in the molecular rearrangement into a different conformational structure. The STEP method possesses several distinct advantages over other techniques currently in use: it is capable of furnishing both time and frequency information, the spectral assignments are unambiguous, and it has high sensitivity. These make the STEP method an ideal tool for studying the energy transfer and chemical reactions in polyatomic systems. ***
