Effect of the internal rotation of the CHD2 group on the CH stretching infrared and Raman spectra of toluene C6D5CHD2 and nitromethane NO2CHD2 in vapor phase
Effect of the internal rotation of the CHD2 group on the CH stretching infrared and Raman spectra of toluene C6D5CHD2 and nitromethane NO2CHD2 in vapor phase
复制标题
CHD2基团的内旋转对气相甲苯C6D5CHD2和硝基甲烷NO2CHD2的CH伸缩红外和拉曼光谱的影响
DOI：
10.1016/0022-2852(82)90089-3
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
J. Lascombe
中科院分区：
文献类型：
--
作者：
D. Cavagnat;J. Lascombe
在CH伸缩区记录了甲苯C6 D5 CHD 2和硝基甲烷NO2 CHD 2的气相红外和拉曼光谱。它们都具有强带和低频弱带的特征。这些谱带具有简单的拉曼谱，红外轮廓分别为A型和C型。在绝热近似下，假设νCH模与CHD 2群的内转动存在非谐耦合，提出了这些谱的量子理论。基于此模型的理论计算给出了一个很好的拟合的实验拉曼带形和所观察到的红外光谱的一个很好的图片。因此，可以表征每个观察到的条带。强带的频率是CHD 2群几乎自由内旋转时νCH模频率的平均值，而弱带的频率近似等于νCH模的最小频率。最后一个对应于CH键在垂直于分子平面的平面中的位置（ν <$CH）。对于这两种化合物，发现ν <$CH（CH键在分子平面内）和ν <$CH之间的频率差为42 cm− 1。
Gas-phase infrared and Raman spectra of toluene C6D5CHD2and nitromethane NO2CHD2were recorded in the CH stretching region. They are all characterized by a strong band with a weaker one at lower frequency. These bands have simple Raman profiles and their infrared contours are respectively ofAandCtype. A quantum theory of these spectra is put forward, assuming an anharmonic coupling of the νCH mode with the internal rotation of the CHD2group in the adiabatic approximation. Theoretical calculations based on this model give a good fit of the experimental Raman bandshapes and a good picture of the observed infrared spectra. Thus each of the observed bands can be characterized. The frequency of the intense band is the average of that of the νCH mode during the almost free internal rotation of the CHD2group, while the frequency of the weaker band is approximately equal to the minimal νCH frequency. This last one corresponds to the position of the CH bond in a plane perpendicular to that of the molecule (ν⊥CH). The frequency difference betweenν∥CH (the CH bond being in the plane of the molecule) andν⊥CH is found to be 42 cm−1for the two compounds.