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.