Spectroscopic identification of jet-cooled 2,4-dichlorobenzyl radicals generated by corona discharge

► We produce the jet-cooled 2,4-dichlorobenzyl radical by corona discharge. ► We observe the first visible vibronic emission spectra of the 2,4-dichlorobenzyl radical. ► We determine the spectroscopic data on the electronic transition and vibrational modes. ► We explain substituent effect of Cl substitutions on electronic energy of the D1-D0 transition.