Molecular spectra and dissociation dynamics of SO₂F₂ under external electric fields

Abstract

Sulfuryl fluoride (SO 2 F 2 ) is a powerful greenhouse gas that threatens human health. It is essential to study the dissociation mechanism of SO 2 F 2 under external electric fields (EEFs). Based on M06-2X/6-311G(d, p) level, the stepwise and concerted dissociation properties of SO 2 F 2 have been investigated under EEFs, including the dipole moment, bond lengths, total energy, orbital energy level distribution, and infrared spectrum. With increasing external-electric-field intensity, the 1S-4F and 1S-5F bonds become longer, the total energy decreases, and the energy gap decreases. Infrared spectroscopy shows that the vibration frequencies of the 1S-4F and 1S-5F bonds decrease as the electric-field intensity increases, and a significant red shift occurs. Time-dependent density functional theory was used to calculate the ultraviolet-visible absorption spectrum. Additionally, the potential-energy curves along the 1S-4F and 1S-5F bonds under electric fields were calculated. The results show that stepwise dissociation of the 1S-4F and 1S-5F bonds occur when F = 0.08 and 0.06 a.u., respectively. Corrected dissociation occurs when F = 0.95 a.u. The spectrum and dissociation mechanism of SO 2 F 2 under EEFs provide a basic understanding of the molecular structure and degradation kinetics of SO 2 F 2 , and it provides insight into decomposition of SO 2 F 2 .