Spectroscopic identification of isomeric jet-cooled benzyl-type radicals formed from 3-fluoro-o-xylene by corona discharge

By means of a pinhole-type glass nozzle designed for supersonic jet expansion along with corona discharge, vibronically excited but jet-cooled isomeric benzyl-type radicals were generated from the precursor 3-fluoro-o-xylene. The visible vibronic emission spectrum was recorded from the discharge system with a long-path monochromator. From an analysis of the spectrum observed, we identified the formation of two isomers, 2-methyl-3-fluorobenzyl and 2-methyl-6-fluorobenzyl radicals in the corona discharge of precursor, and determined for the first time the electronic energy in the D1 → D0 transition and vibrational mode frequencies in the D0 state for both isomers.