Observation of vibronic emission spectrum of jet-cooled 4-chloro-m-xylyl radical

We report the vibronic emission spectrum of 4-chloro-m-xylyl radical using a long-path monochromator in a corona-excited supersonic expansion (CESE). By the precursor 4-chloro-m-xylene, we identified 4-chloro-m-xylyl from the two isomeric benzyl-type radicals analyzing a Franck-Condon simulation and ab initio calculations. From an analysis of the vibronic emission spectrum of the 4-chloro-m-xylyl radical, the D-1 -> D-0 electronic transition energy was confirmed and the assignments of vibrational frequencies were accomplished in the ground state.