Spectroscopic identification of jet-cooled o-ethynylbenzyl radical generated in corona discharge

Abstract The vibronically excited but jet-cooled o -ethynylbenzyl radical was generated from precursor, o -ethynyltoluene seeded in a large amount of carrier gas helium using a home-made pinhole-type glass nozzle combined with the technique of corona excited supersonic expansion. The visible vibronic emission spectrum was recorded with a long-path monochromator from the corona discharge of the precursor. By analyzing the observed spectrum, we determined the electronic energy in the D 1  → D 0 transition and vibrational mode frequencies in the D 0 electronic state of the o -ethynylbenzyl radical.