Vibronic Spectroscopy of Jet-Cooled Benzyl-type Radicals Produced from 2-Fluoro-4-Chlorotoluene by Corona Discharge
作者:Sang Youl Chae、Young Wook Yoon、Sang Kuk Lee
DOI:10.5012/bkcs.2013.34.12.3565
日期:2013.12.20
A home-made pinhole-type glass nozzle was employed to generate vibronically excited but jet-cooled benzyl-type radicals from precursor 2-fluoro-4-chlorotoluene with a large amount of carrier gas He, from which the visible vibronic emission spectrum was recorded with a long-path monochromator. From an analysis of the spectrum observed, it was found that two benzyl-type radicals, 2-fluorobenzyl and 2-fluoro-4-chlorobenzyl radicals, were formed from the precursor in corona discharge. The possible pathway for the production of benzyl-type radicals that can explain the spectroscopic observation is herein proposed. In addition, the electronic energy of the $D_1\rightarrow}D_0$ transition and the vibrational mode frequencies in the $D_0$ state of the 2-fluoro-4-chlorobenzyl radical were determined for the first time.
利用自制的针孔型玻璃喷嘴,在大量载气 He 的作用下,从前驱体 2-氟-4-氯甲苯中产生了振子激发但喷射冷却的苄基自由基,并用长路径单色仪记录了可见振子发射光谱。通过对观察到的光谱进行分析,发现前驱体在电晕放电过程中形成了两个苄基自由基,即 2-氟苄基和 2-氟-4-氯苄基自由基。本文提出了产生苄基自由基的可能途径,从而解释了光谱观测结果。此外,还首次测定了 2-氟-4-氯苄自由基的 $D_1\rightarrow}D_0$ 转变的电子能量和 $D_0$ 态的振动模式频率。