Phosgene (COCl2), a colorless and highly toxic gas, rapidly decomposes into phosgene from chlorinated solvents used in industry, polluting the environment. The study of the properties and dissociation methods is of great value in reducing pollution. In this paper, the physical and chemical properties of COCl2 under the action of an applied electric field (0–12.855 V nm–1), including bond lengths, total energies, electric dipole moments, LUMO-HOMO energy gaps, infrared spectra, Raman spectra, dissociative potential energy surfaces, and excited states, are investigated based on the density-frequency functional theory (DFT) at the BPV86/6-311G+(2d,p) level. IR and Raman spectra exhibit redshifts and intensity changes as the applied electric field increases. This study also determines the range of control for the electric field based on the tunneling effect. Using the same optimization method, the potential energy curves were obtained by scanning the single-point energy along the C=O bond, and the dissociation properties were obtained by fitting the linear curve of the potential barriers under the applied electric field, which showed a gradual decrease of the dissociation barrier, and the field corresponding to the zero potential barrier was calculated. In addition, the Ultraviolet–visible spectroscopy (UV–Vis) of COCl2 was obtained by using TD-SCF/6-311G+(2d,p) with a gradual redshift with an increasing applied electric field and a general decreasing trend of excitation energy. The results of the study provide an important theoretical basis for the in-depth study of COCl2, reflecting the significant changes in the structure and properties of phosgene molecules under external electric fields and providing an important theoretical basis for the degradation of COCl2 to achieve sustainable development.
Sun et al. (Sun,) studied this question.