Global Modeling of Ar-CF₄ Plasma Chemistry in a Dielectric Barrier Discharge

A global model that integrates a multi-term Boltzmann solver, has been developed to examine the Ar-CF₄ chemistry in an atmospheric pressure dielectric barrier discharge (DBD). In this paper, the reactive species production was explored to unravel the mechanism behind the superior endotoxin deactivation effectiveness of fluorine-containing gases (CF₄, SF₆) in an atmospheric pressure DBD. The model includes a comprehensive set of 202 reactions involving 34 reactive species, calculating heavy particle reaction rates using Arrhenius forms, and electron impact reaction rates using a multi-term 0-D Boltzmann solver, MultiBolt. MultiBolt was employed to improve accuracy compared to the conventional two-term approximation, especially at high E/N and with gas mixtures having large inelastic cross sections. Rapid dissociative charge exchange produces CF₃⁺ ions. CF₃ and F emerge as the dominant reactive neutral species, with the CF₃ rate increasing significantly with CF₄ concentration. Despite abundant Ar* and Ar₂* excited states, the high ionization energy of CF₄ (14.7 eV) limits their chemical contribution. The effect of pulse duration, CF₄ admixture, and applied power on the reactive species production will be discussed. Future work includes comparisons to experiments to identify the species crucial for toxin deactivation, to guide selection of operational parameters for efficient destruction of toxins.