外电场下 4 - 氟苯酚分子的分子结构和解离特性.

4 - Fluorophenol is a widely used aromatic compound and one of toxic organic pollutants, which has great harm to the environment and human body. It is of great significance to study its degradation mechanism under external electric field. In this paper, the density functional method ( DFT) and the time - dependent density universal method (TD - DFT) are used to study the geometric structure, spectral characteristics and dissociation characteristics of 4 - fluorophenol molecules under different applied electric fields ( 0 - 0. 03 a. u. ) at the B3LYP/ 6 -311 G + (2d,2p) basis set level. The results show that the applied electric field has a great influence on the structure and properties of 4 - fluorophenol molecules. With the increase of the external electric field in the direction of X ( C - F bond), the bond length of C - F bond of 4 - fluorophenol molecules increases, the total energy of molecular system gradually decreases, the dipole moment gradually increases and the energy gap gradually decreases. The strongest peak of the infrared spectrum of 4 - fluorophenol molecule is red - shifted, the peak value of the absorption peak of ultraviolet absorption spectrum first increases and then decreases, and the dissociation potential energy of 4 - fluorophenol molecule gradually decreases, which indicates that 4 - fluorophenol molecule tends to dissociate under the action of external electric field. This study provides a reference for the degradation of 4 - fluorophenol pollutant molecules by external electric field. [ABSTRACT FROM AUTHOR]