Professors Bernstein and Kelley are supported by the Experimental Physical Chemistry Program in a collaborative study of vibrational energy dynamics in excited electronic states of small solute/solvent clusters and of solute dimers formed in a supersonic molecular jet expansion. These measurements will help elucidate the relative importance of various radiationless processes involved in redistributing the initial energy into other degrees of freedom. Optical excitation will prepare the clusters with known amounts of vibrational energy in the first excited singlet state of the solute chromophore. The vibrational dynamics will be monitored by picosecond spectroscopic studies of the rise and decay times of the population in specific vibronic levels of both the pumped parent cluster and the free molecule resulting from predissociation. Measurements will include time-resolved emission, two color ionization, and two color stimulated emission pumping. The solute chromophores will be aromatic azines, and the solvents will include ammonia, water, methane, deuterated methane, argon, and carbon tetrafluoride.
