Non equilibrium vibrational assisted dissociation and ionization mechanisms in cold CO 2 plasmas

Upper limits rates of pure vibrational dissociation mechanisms of CO2 in discharge and post discharge conditions have been compared with the direct electron impact rates from the ground vibrational level as well as including transitions from a multitude of vibrational states. At low reduced electric field E/N values and, mostly, in the post discharge regime (E/N = 0), the pure vibrational rates exceed the corresponding ones from electron impact dissociation mechanisms, showing the importance of vibrational excitation in the dissociation of CO2. Comparison of ground vibrational state ionization rate with the corresponding one, which takes into account ionization transitions from excited vibrational levels, shows large difference in both discharge and post discharge conditions. The accuracy of the results largely depends on the number of vibrational levels included in the Boltzmann equation as shown by inserting, in the Boltzmann solver, all electron-vibration transitions involving the asymmetric vibrational levels of the CO2 molecule.