Spectroscopic evidence of α,α-dichlorobenzyl radical produced by corona discharge of benzotrichloride

Abstract We report spectroscopic observations of the α,α-dichlorobenzyl radical obtained by corona excited supersonic jet expansion using a pinhole-type glass nozzle. Vibronically excited but jet-cooled radicals were generated by corona discharge of the precursor benzotrichloride with a large amount of helium carrier gas, from which the visible vibronic emission spectrum was recorded using a long path monochromator. From an analysis of the spectrum observed, the electronic energy of the D 1  → D 0 transition and a few vibrational mode frequencies in the ground electronic state were obtained for the α,α-dichlorobenzyl radical by comparing observed frequencies with those obtained by ab initio calculation.