Spectroscopic study of Methylbenzyl radicals in a corona excited supersonic expansion

Chang soon Huh

Methylbenzyl radical, Corona Excited Supersonic Expansion(CESE), Vibronic Emission Spectrum, Ab initio Calculation

We report the spectroscopic and ab initio and spectroscopic evidence of the 1, 3, 5- trimethylbenzyl and 3, 5-dimethylbenzyl radical in corona excited supersonic expansion(CESE). The electronically hot but jet-cooled 1, 3, 5- trimethylbenzyl and 3, 5-dimethylbenzyl radical has been produced from precursor 1, 2, 3-trimethylbenzene seeded in large amount inert carrier gas helium by using the technique of CESE with a pinhole-type glass nozzle. AB initio calculation were carried out with the GAUSSIAN-09 package and vibronic emission spectrum of the 3,5-dimethylbenzyl radicals were recorded with a long path monochromator in the D₁ → D₀ electronic transition in the visible region. Ab initio calculation of the ground-state benzyl radical have been carried out with density functional method and the complete basis set model. The observed spectrum is consistent with the result of vibrational frequencies of the ab initio calculation and the benzyl radical ground state reaction mechanism through the hydrogen migration is presented. Furthermore, the ab initio calculation explains the benzyl radical generation mechanism in the excited state through the anti-bonding energy surface.