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Doctor of Philosophy




SVL fluorescence spectroscopy was used to study intra- molecular energy transfer from the 0(DEGREES) level of aniline induced by collisions with CO(,2). The populations of eight aniline vibronic growth levels, as a function of CO(,2) pressure, were monitored. Collision gas pressures were adjusted to keep aniline-CO(,2) interactions within the single-collision regime. To first order, collision-induced energy transfer from the 0(DEGREES) level of aniline for CO(,2) as the collision gas follows the same flow pattern as was found in previous studies when Ar, H(,2)O or CH(,3)F were the collision partners('1,2);Time-correlated photon counting was used to measure concen- tration dependent fluorescence depolarization for rhodamine 6G in glycerol. Fluorescence decays from these viscous solutions provide data for analyzing the three-dimensional, three-body excitation transport theory developed by Gochanour, Andersen and Fayer for disordered systems('3). Solution concentrations of rhodamine 6G range from 1.7 x 10('-4) to 2.4 x 10('-3) M. Differences between optimized theoretical and experimental profiles are shown to be dominated by experimental artifacts arising from excitation trapping by rhodamine 6G aggregates and from self-absorption in solution cells thicker than 10 (mu)m;The two-dimensional, two-body excitation theory developed by Loring and Fayer('4) was also examined using time-resolved fluores- cence depolarization techniques. The samples, made up of sub- monolayers of rhodamine 3B adsorbed onto optically flat fused silica yield fluorescence profiles which agree well with profiles developed from the theory for reduced surface coverages up to (TURN)0.4. At higher coverages, excitation trapping by rhodamine 3B aggregates;truncates the depolarization process, yielding apparent reduced coverages which are appreciably lower than the true coverages; ('1,2,3,4)Please see dissertation for references.



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John Francis Hedstrom



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328 pages