Knowledge Bank

\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 $A~2$A-$X~2$A electronic transition of phenyl peroxy radical. \textit{Ab initio} calculations have been carried out to help assign T$\mathrm{<mrow\; data-mjx-texclass="ORD">00</mrow>}$ band origin, as well as other vibrational bands.