Self-Consistent State-to-State Kinetic Modeling of CO2 Cold Plasmas: Insights on the Role of Electronically Excited States

Abstract

AbstractThis study focuses on the role of CO2 and CO electronically excited states in the kinetics of CO2 cold non-equilibrium plasma discharges by means of a state-to-state OD kinetic model based on the simultaneous and self-consistent solution of the electron Boltzmann equation and the master equations describing the vibrationally and electronically excited state kinetics and the plasma composition. A new CO2 dissociation model based on the use of the Biagi electron impact excitation cross sections, considered as fully dissociative, of several CO2 electronic excited states, in the energy range from 6.5 to 25 eV, is tested and compared with the results obtained by using the Phelps database in typical glow and microwave discharge conditions. Moreover, a refinement of the kinetics of the $$\mathrm{CO}\left({\mathrm{a}}^{3}\Pi \right)$$ CO a 3 Π excited state is proposed by including new production and loss terms and the effect of the change of its time evolution density on the eedf, the electron temperature, the CO2 and CO vibrational distribution functions, electron impact and vibrational induced dissociation rates is investigated. Finally, the contribution of the $$\mathrm{CO}\left({\mathrm{a}}^{3}\Pi \right)$$ CO a 3 Π state to CO2 dissociation is examined in terms of production and recombination (or back-reaction) processes both in microwave and glow discharge conditions.