Department of Physics, Udai Pratap Autonomous College, Varanasi 221002, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 Nov;77(4):787-94. doi: 10.1016/j.saa.2010.08.005. Epub 2010 Aug 10.
Raman and FTIR spectra of the 2,3,6-tri-fluorobenzoic acid molecule have been recorded in the regions 50-4000cm⁻¹ and 400-4000cm⁻¹, respectively. Vibrational frequencies have been calculated by employing DFT method in dimeric form in optimum state. SQM force field has also been used to calculate potential energy distributions in order to make conspicuous vibrational assignments. Raman activities calculated by DFT method have been converted to the corresponding Raman intensities using Raman scattering theory. Optimized bond lengths and angles of the title molecule have been interpreted and compared with the earlier reported experimental values for benzoic acid and some mono and di-fluorinated benzoic acids. Some of the vibrational frequencies of the title molecule are effected upon profusely with the fluorine substitutions in comparison to benzoic acid and these differences have been interpreted. The strong doubly hydrogen-bonded interface of the dimerized system is well demonstrated by the red shift in OH stretching frequency concomitant with the elongation of bond length.
已经记录了 2,3,6-三氟苯甲酸分子在 50-4000cm⁻¹ 和 400-4000cm⁻¹ 区域的拉曼和傅里叶变换红外光谱。通过在最佳状态下采用 DFT 方法在二聚体形式下计算了振动频率。还使用 SQM 力场来计算势能分布，以便进行明显的振动分配。通过 DFT 方法计算的拉曼活性已转换为相应的拉曼强度，使用拉曼散射理论。解释了标题分子的优化键长和键角，并与苯甲酸和一些单氟和二氟苯甲酸的早期报道的实验值进行了比较。与苯甲酸相比，标题分子的一些振动频率在氟取代时会受到很大影响，并且已经对这些差异进行了解释。通过 OH 伸缩频率的红移伴随着键长的伸长，很好地证明了二聚化系统的强双氢键界面。
