15min:

YOUNG WOOK YOON, SEUNG WOON LEE, SANG KUK LEE, Department of Chemistry, Pusan National University, Pusan 609-735, South Korea; AND GI WOO LEE, Korea Basic Science Institute, Pusan 609-735, Korea.

Using a pinhole-type glass nozzle coupled with corona excited supersonic expansion (CESE), precursors o- and p-chloro-ethylbenzenes seeded in a large amount of inert carrier gas helium were corona discharged to produce jet-cooled benzyl-type radicals. The vibronic emission spectra were recorded with a long path monochromator to observe vibronic bands of benzyl-type radicals in the visible region. The analysis of the spectra shows the evidence of the o- and p-chlorobenzyl radicals as typical products in corona excitation as well as the o- and p-chloro- -methylbenzyl radicals as unexpected species. After subtracting the bands belonging to chlorobenzyl radicals, we could construct the vibronic emission spectra of the o- and p-chloro- -methylbenzyl radical in the D₁ D₀ electronic transition at the gas phase. By comparing with those of ab~ initio calculation and of the known vibrational mode frequencies with similar structures, we could obtain the electronic transition and assign the vibrational modes to the bands observed.