• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.763-767
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• 2013

We resolved the controversial assignments of the visible vibronic bands observed from corona discharge of 1,2,3-trimethylbenzene. The vibronic bands belonging to the jet-cooled 2,6-dimethylbenzyl radical were clearly identified from the spectrum observed from corona discharge of 2,6-dimethylbenzyl chloride. After subtracting the bands of the 2,6-isomer from the spectrum observed from corona discharge of 1,2,3-trimethylbenzene, the vibronic bands of the 2,3-isomer were also identified. By comparing data with the known vibrational data of 1,2,3-trimethylbenzene and the results of ab initio calculations, we determined the electronic energies of the $D_1{\rightarrow}D_0$ transitions and vibrational mode frequencies in the ground electronic states of the 2,3-and 2,6-dimethylbenzyl radicals.

• Bulletin of the Korean Chemical Society
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• v.29 no.12
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• pp.2341-2345
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• 2008

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.1993-1995
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• 2007

A substitution effect on the electronic transition of bi-substituted benzyl-type radicals was discovered. The origin of the electronic D1 → D0 transition of benzyl-type radicals was red-shifted upon substitution to the benzene ring. For symmetric bi-substituted benzyl-type radicals, it was found that the predicted shift obtained from mono-substituted benzyl-type radicals agreed well with the observation. The reason for this agreement is believed that the substituent contributes independently to the electronic energy. The substitution effect was applied to the symmetric bi-substituted difluoro-, dichloro- and dimethylbenzyl radicals.