Spectroscopic characteristics and dissociation of nitrogen trifluoride under external electric fields: Theoretical study

Abstract

Abstract The dissociation of nitrogen trifluoride (NF3) is an important topic of study because the molecule is a highly dangerous greenhouse gas that can persist in the atmosphere for 740 years. In this study, changes in the geometry, orbital energy, spectral properties, and dissociation properties of NF3 when an external electric field was applied were studied by density functional theory. Results show that when the strength of the electric field was increased, the N–3F bond length became longer until it broke, and the energy gap decreased gradually. The dissociation barrier in the potential energy curve gradually decreased with the increase in the electric field strength. When the applied electric field reached 0.05 a.u., the dissociation barrier disappeared, indicating that under the action of a strong applied electric field, NF3 is degraded because of fracture of the N–3F bond. When the application of the electric field was continued, the potential barrier disappeared and dissociation occurred when the N–4F bond was scanned. The stepwise dissociation of nitrogen trifluoride molecules occurred under an electric field intensity of 0.05 a.u. The concerted dissociation of the N–3F and N–4F bonds occurred at an electric field intensity of 0.09 a.u. When the electric field direction was in the negative direction of the z-axis, the NF3 dissociated but no concerted dissociation occurred. These results offer insight into the degradation mechanism under an applied electric field.