间二甲苯分子结构和红外光谱的密度泛函理论计算的研究

DFT Calculation of Molecular Structure and Infrared Spectrum of M-xylene

用密度泛函理论(DFT)-B3LYP方法在6-31+G(d)基组水平上对间二甲苯的几何构型进行了全优化,得到几何构型参数,进一步对其振动光谱进行了计算.对计算得到的振动频率进行归属和解析并与文献值比较,发现理论计算得到的红外光谱与实验测定红外特征峰位较为吻合.这表明采用(DFT)-B3LYP方法能够预测芳烃类化合物的分子结构和红外光谱数据,从而为该类化合物光谱性质预测及构效关系研究提供依据.

In the present research, the geometrical configuration of m-xylene was optimized by using density-functional theory at the B3LYP/6-31＋ G （d） level, and the geometrical configuration parameters were obtained. Further, its infrared （IR） spectrum was calculated with the same method. The vibrational modes of IR spectrum were assigned and compared with experimental data. It was found that the calculated IR spectral features were in good agreement with the experimental ones. This indicates that DFT is a useful method for the structure optimization and IR spectrum calculation of aromatic compounds derivatives. The theoretical calculation results of IR spectrum can provide useful information for the prediction of spectral property and investigation of structure-activity relationship of aromatic compounds derivatives.