Accession Number : ADA305708

Title :   Photofragmentation Spectroscopy and Photodissociation Dynamics of Polyatomic Molecules.

Descriptive Note : Final rept.,

Corporate Author : PUERTO RICO UNIV RIO PIEDRAS DEPT OF CHEMISTRY

Personal Author(s) : Weiner, Brad R.

PDF Url : ADA305708

Report Date : 01 MAR 1996

Pagination or Media Count : 23

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,Cl 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. A general procedure to evaluate the rotational state population distributions of the nascent photofragments from the photodissociation of polyatomic molecules has been implemented with the use of a kinematic distribution function. Numerical evaluations of rotational state population distributions of diatomic photofragments from photodissociation of the general class of triatomic molecules are presented. 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. jg p2

Descriptors :   *PHOTODISSOCIATION, *POLYATOMIC MOLECULES, *DYNAMICS, *PHOTOFRAGMENT SPECTROSCOPY, KINEMATICS, RADIATION, VIBRATION, FLUORESCENCE, MODELS, REAL TIME, SPECTROSCOPY, PHOTOCHEMICAL REACTIONS, LASER INDUCED FLUORESCENCE, MOLECULES, ENERGY, NUMERICAL ANALYSIS, VAPOR PHASES, ETHYLENE, CHEMISTRY, HALIDES, TRANSITIONS, KINETICS, DISPOSAL, ROTATION, PICTURES, EXCIMERS, DECAY, DISTRIBUTION FUNCTIONS, ANILINES, THIONYL CHLORIDE, SULFUR OXIDES, METHYL SULFOXIDE, DIOXIDES, POPULATION(MATHEMATICS).

Subject Categories : Physical Chemistry
      Radiation and Nuclear Chemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE