OBSERVATION OF THE $\tilde{A} - \tilde{X}$ ELECTRONIC TRANSITION OF THE $CF_{3}O_{2}$ RADICAL
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Date
2001
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Publisher
Ohio State University
Abstract
Fluorinated peroxy radicals form a class of important intermediates in oxidation and atmospheric $destruction^{a}$ of chlorofluorohydrocarbons (CFCs) and hydrofluorocarbons (HFCs). Therefore recently much effort has been devoted to the study of the peroxy kinetics. Detection of peroxy radicals has been largely accomplished via monitoring their broad and structureless $\tilde{B}_{2}A^{\prime\prime} - \tilde{X}^{2}A^{\prime\prime}$ absorption $band^{b}$. A near IR $\tilde{A} - \tilde{X}$ transition has been observed for the $hydroperoxy^{c}$ and for the simplest alkyl peroxy $radicals^{d}$. However for the fluorinated analogues there appear to have been no such observations. Their known spectroscopy seems limited to the above mentioned broad UV transition, vibrational $studies^{e}$ in the $\tilde{X}$ state using matrix isolation techniques and to EPR $studies^{f}$ of the radicals in solution. We report the first observation of a sharp, structured electronic spectrum for a fluorinated alkyl peroxy radical using the technique of cavity ringdown spectroscopy (CRDS). A $T_{00}$ value of $6656(3) cm^{-1}$ for the $\tilde{A}^{2}A^{\prime} - \tilde{X}^{2}A^{\prime\prime}$ transition of $CF_{3}O_{2}$ has been determined, as well as values for some $\tilde{A}$ state vibrational frequencies. Initial kinetic observations on $CF_{3}O_{2}$ have been carried out using CRDS to monitor its concentration.
Description
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Author Institution: The Ohio State University; Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University
Author Institution: The Ohio State University; Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University