| Abstract |
The detailed reaction dynamics of several gas phase polyatomic systems has been established in this research at the Department of Chemistry at the University of Puerto Rico. Real time dynamics of sulfur monoxide photoelimination reactions have been studied by laser induced fluorescence spectroscopy of the nascent SO fragment on the B(3)sigma (-) - X(3)sigma(-) transition in the region of 237-310 nm. The following group of molecules has been studied: Sulfur dioxide (SO2), the thionyl halides (SOX2; where X=F,C1 or Br), dimethyl sulfoxide ((CH3)2SO), ethylene episulfoxide ((CH2)2SO), trimethylene sulfoxide ((CH2)3SO), tetramethylene sulfoxide ((CH2)4SO), and thionyl aniline (C6H5NSO). In all of these experiments, the parent molecule is irradiated with an excimer laser (either 193 or 248 nm) and the energy disposal into the nascent SO photofragment is determined, and used as a mechanistic probe. A broad picture of sulfur monoxide photoelimination reactions emerges from this work. In a second area, the photophysics and photochemistry of the vinoxy radical were investigated. Fluorescence decay rates were determined in the presence of twelve collision partners: He, Ar, N2, O2, CO, H2, HCl, CO2, N2O, C2H4, SF6 and CH3OCH=CH2. The measured electronic quenching cross-sections vary from 0.01 - 66.5 A2. A vibrational level dependence was found for the radiative lifetimes. A kinetic model, consistent with all the experimental observations has been postulated. Several new transitions of the CH2CHO (B-X) transition have been discovered. Finally, a study of bimolecular reactions has been initiated. jg p2. |
