Spectroscopic observation of jet-cooled 2-chloro-m-xylyl radical

We report the first spectroscopic observation of the 2-chloro-m-xylyl radical in the gas phase. The vibronically excited but jet-cooled 2-chloro-m-xylyl radical was generated from the corona discharge of the precursor, 2-chloro-m-xylene seeded in a large amount of inert carrier gas He. The well-resolved vibronic emission spectrum of the 2-chloro-m-xylyl radical was recorded using a long path monochromator in the visible region. The spectrum was analyzed to obtain accurate measurements of the energy of the D1 → D0 electronic transition and the vibrational modes frequencies in the ground electronic state by comparison with those from an ab initio calculation and the known vibrational data of the precursor.