Vibronic spectrum of the jet-cooled 2,6-dimethylbenzyl radical in a corona excitation

A jet-cooled 2,6-dimethylbenzyl radical was generated for the first time from a precursor 2,6-dimethylbenzyl chloride with a large amount of inert carrier gas He in a corona-excited supersonic expansion using a pinhole type glass nozzle. The visible fluorescence emanating from the jet was recorded with a long path monochromator to observe the vibronically resolved jet-cooled emission spectrum. The spectrum was analyzed to obtain accurate electronic transition and active vibrational mode frequencies in the ground electronic state by comparison with those from an ab initio calculation.