BENZYL, TROPYL, AND NORBORNADIENYL

Benzyl radical (C$_{6}$H$_{5}$CH$_{2}$) and two other C$_{7}$H$_{7}$ radicals are commonly encountered in the combustion of substituted aromatic compounds found in biofuels and gasoline. High temperature pyrolysis of benzyl radical requires isomerization to other C$_{7}$H$_{7}$ radicals that may include cycloheptatrienyl (tropyl) radical (textit{cyc}-C$_{7}$H$_{7}$) and norbornadienyl radical. The thermal decomposition of all three radicals has now been investigated using a micro-reactor that heats dilute gas-phase samples up to 1600 K and has a residence time of about 100 $mu$-sec. The pyrolysis products exit the reactor into a supersonic expansion and are detected using synchrotron-based photoionization mass spectrometry and matrix-isolation IR spectroscopy. The products of the pyrolysis of benzyl radical (C$_{6}$H$_{5}$CH$_{2}$) along with three isotopomers (C$_{6}$H$_{5}^{13}$CH$_{2}$, C$_{6}$D$_{5}$CH$_{2}$, and C$_{6}$H$_{5}$CD$_{2}$) were detected and identifiedfootnote{Buckingham, G. T., Ormond, T. K., Porterfield, J. P., Hemberger, P., Kostko, O., Ahmed, M., Robichaud, D. J., Nimlos, M. R., Daily, J. W., Ellison, G. B. 2015, Journal of Chemical Physics textbf{142} 044307}. The distribution of $^{13}$C atoms and D atoms indicate that multiple different decomposition pathways are active. begin{wrapfigure}{l}{0pt} includegraphics[scale=0.45]{C7H7_radicals.eps} end{wrapfigure