Vibronic emission spectra of jet-cooled 2,3-difluorobenzyl radical in a corona excited supersonic expansion

We report the spectroscopic observation of difluorobenzyl radical in a corona excited supersonic expansion using a pinhole-type glass nozzle. A jet-cooled 2,3-difluorobenzyl radical was generated and vibronically excited from 2,3-difluorotoluene seeded in a large amount of inert carrier gas He. The vibronic emission spectra of the jet-cooled 2,3-difluorobenzyl radical were recorded for the first time in the visible region and analyzed to obtain an accurate measurement of the vibronic transition energy between the D1 and D0 electronic states. The vibrational mode frequencies in the ground electronic state were determined by comparison with those from an ab initio calculation as well as those of 2,6-difluorobenzyl radical and 1,2,3-trimethylbenzene.