Department of Physics, Udai Pratap Autonomous College, Varanasi 221002, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Oct 15;81(1):609-19. doi: 10.1016/j.saa.2011.06.063. Epub 2011 Jun 30.
The theoretical IR and Raman spectra of the 2,3,4-, 2,3,6-, 2,4,5- and 3,4,5-tri-fluorobenzonitrile molecules have been calculated by using the density functional method in the ground state. The rigorous normal coordinate analyses based upon both an empirical force field and quantum chemical calculations have been performed and the detailed vibrational assignment has been made on the basis of the calculated potential energy distributions (PEDs). A comparison of molecular geometries, atomic charges and vibrational fundamentals of these molecules has been reported. The effects of fluorination upon the geometries, atomic charges and vibrational frequencies of benzonitrile have been discussed. Several ambiguities and contradictions in the previously reported vibrational assignments have been clarified. In addition, the variation of Raman intensity with excitation frequency and with temperature has also been studied.
采用密度泛函理论在基态下计算了 2,3,4-、2,3,6-、2,4,5-和 3,4,5-三氟苯甲腈分子的理论红外和拉曼光谱。基于经验力场和量子化学计算进行了严格的正则坐标分析，并根据计算的势能分布（PED）进行了详细的振动归属。报道了这些分子的分子几何形状、原子电荷和振动基频的比较。讨论了氟取代对苯甲腈的几何形状、原子电荷和振动频率的影响。澄清了先前报道的振动归属中的一些歧义和矛盾。此外，还研究了拉曼强度随激发频率和温度的变化。
