Study on Pyrolysis Characteristics of SF(6) in a Trace-Oxygen (O(2)) Environment: ReaxFF(SFO) Force Field Optimization and Reactive Molecular Dynamics Simulation

[Image: see text] The ReaxFF(SFO) force field for a SF(6)–O(2) system is developed based on the density functional theory (DFT) calculation data. Then, a series of molecular dynamics (MD) simulations were performed. The results show that the main oxygen-containing compounds that appeared in the MD simulation include SOF(4), SOF(2), and SO(2)F(2). The relative quantitative relationship between SOF(2) and SOF(4) can be used to determine the fault temperature. Besides, under overheating conditions, O(2) rarely undergoes a self-cracking process to generate free O atoms. Instead, the basic route for O(2) to participate in the SF(6) pyrolysis process is X + Y + O(2) = XO + YO. Furthermore, the reactivity order of various groups to O(2) is (SF(2))* > (SF(3))* > (SF(4))* > F*, so O(2) is more likely to participate in the reaction by attacking (SF(3))* or (SF(2))* groups. This study laid the foundation for the application of ReaxFF MD simulations to study the microscopic dynamic mechanism of SF(6) pyrolysis in more complex systems.