Kinetic studies following state-selective laser excitation. Progress report, March 15, 1981-March 14, 1983

In the past contract period, we initiated studies of excitation transfer reactions from excited states of xenon atoms and excimers produced selectively by two photon laser excitation. Work in the initial period has concentrated on several phases of the program. We have made laser spectrographic studies of pure rare gases to verify our calculated two photon transition rate, to identify the atomic and molecular species of interest, and to determine branching fractions for product states in collisions of excited rare gas atoms with other rare gases. We have continued development of a high repetition rate picosecond laser which operates in the uv. Combined with channel plate photomultipliers we will be able to measure decay times on the order of 20 psec with the precision of the single photon delayed coincidence techniques. We are building a new apparatus featuring a high-pressure flow reactor. The flow reactor will enable us to study energy transfer to molecular reactants. In spectrographic experiments we find that laser excitation when detuned from an atomic resonance can excite atoms during a collision at a particular internuclear separation. We observe that atoms which are excited during a collision react quite differently than atom excited at atomic resonances