Non-equilibrium electronic and vibrational kinetics in H2-N2and H2discharges

In the first section of this paper, the results from a systematic theoretical study describing the electron kinetics and the heavy particle kinetics of H 2 in glow discharges through H 2 -N 2 mixtures are presented. The results show that the collisional interactions between the vibronic states of H 2 , N 2 are highly nonlinear, and that they strongly affect the dissociation, ionization, gas heating, discharge impedance and power loading. It is shown that at low discharge currents (<80 mA), medium gas pressures (>1 Torr), and approximately=10-80%H 2 -N 2 gas mixture composition, quenching of the excited electronic states of N 2 by H 2 is the dominant dissociation channel of H 2 in %H 2 -%N 2 discharges. The results further demonstrate that the dissociation balance and the electronic/ionization balance in these molecular glow discharges are strongly coupled and that neither can be studied independently of the other. In the second section of this study, a revised kinetic analysis of the formation of atomic H - negative ions in volume sources is presented. A new process for the production of H - is introduced in the analyses. Using data derived from recent experiments, it is shown that the contribution to H - formation from dissociative attachment to the high Rydberg states of H 2 is comparable to (or greater than) that from H 2 (X 1 Sigma g + ,V). This additional source term for H - production may resolve some of the problems in understanding the H - densities in low-pressure H 2 plasmas.