Visible emission spectroscopy of jet-cooled chloro-substituted 2-methylbenzyl radicals

Abstract Four isomeric chloro-substituted 2-methylbenzyl radicals were generated from the corona discharge of 3- and 4-chloro- o -xylenes seeded in a large amount of He carrier gas using a technique of corona excited supersonic expansion coupled with a pinhole-type glass nozzle. The observed visible vibronic emission spectra were analyzed to identify the radical species produced in the discharge, from which the production of the 3-, 4-, 5-, and 6-chloro-2- methylbenzyl radicals was confirmed. In addition, we determined the D 1  → D 0 electronic transition energies and vibrational mode frequencies in the D 0 state of the isomeric chloro-substituted 2-methylbenzyl radicals.