CAVITY RINGDOWN SPECTROSCOPY OF THE $\widetilde{A}^{2}$A$^{\prime}$ - $\widetilde{X}^{2}$A$^{\prime\prime}$ ELECTRONIC TRANSITION OF THE PHENYL PEROXY RADICAL

{M. B. Pushkarsky, S. J. Zalyubovsky, and T. A. Miller, \textit{J. Chem. Phys{S. Zalyubovsky, B. Glover, T. A. Miller, C. Hayes, J. K. Merle, and C. M. Hadad, \textit{J. Chem. PhysAuthor Institution: Laser Spectroscopy Facility, Department of Chemistry, The Ohio; State University, Columbus, OH 43210\maketitle Peroxy radicals are key intermediates in bothcombustion and atmospheric chemistry. We have previously studied small alkyl peroxy radicals (methyl, ethyl peroxy} \underline{\textbf{112}}, 10695, (2000).}, 1- and 2-propyl peroxy} accepted}) via their near IR electronic transition using cavity ringdown spectroscopy (CRDS). The reaction of phenyl radical (C$_6$H$_5$) with oxygen is postulated to play a particulary important role in the soot formation process inherent in hydrocarbon combustion. In this talk, we report CRDS of the near IR $\widetilde{A}^{2}$A$^{\prime}$-$\widetilde{X}^{2}$A$^{\prime\prime}$ electronic transition of phenyl peroxy radical. \textit{Ab initio} calculations have been carried out to help assign T$_{00}$ band origin, as well as other vibrational bands