Spectroscopic identification of jet-cooled p-fluoro-α-methylbenzyl radical in corona discharge

We report the first spectroscopic identification of the p-fluoro-α-methylbenzyl radical in the gas phase. Precursor p-fluoro-ethylbenzene seeded in a large amount of carrier gas was electrically discharged to produce the benzyl-type radicals in a corona excited supersonic expansion using a pinhole-type glass nozzle, from which the vibronic emission spectrum was recorded in the visible region. From an analysis of the spectrum observed, we identified spectroscopically the formation of the p-fluoro-α-methylbenzyl, in which the energy of the D1 → D0 electronic transition and a few vibrational mode frequencies in the ground electronic state were determined by comparison with those from an ab initio calculation and with those from the known data of the precursor.