ИСТИНА

N2 dissociation in pure nitrogen plasma has a long histiry of research. It seems to be a complex process which comprises many reactions involving various electronic and vibrational nitrogen states whose contributions can vary depending on conditions. Here we studied N2 dissociation in the stationary N2 discharge both experimentally and theoretically. We used a DC glow discharge in quartz tube in pure N2 at moderate pressures (5-50 Torr). Dissociation degree, the atomic nitrogen loss frequency and gas temperature were measured by applying optical emission spectroscopy (OES) and as a result an "effective" rate constant for nitrogen dissociation was obtained in the wide range of reduced field E/N. The analysis of N2 dissociation was carried out using specially developed 1-D radial self-consistent model which takes into account the spatially inhomogeneities od species concentrations, E/N, EEDF, Tgas, etc together with fairly complete plasma-chemical kinetics and all the known up-to-date cross-sections dor electron kinetics. The model was successfully validated through the obtained experimental results for elctric field, gas temperature and N atom density. The comprehensive analysis of closely coupled processes in nitrogen plasma - ionization, gas heating and n2 dissociation, were carried out. Simulation reproduced well the experimental data and allowed us to evaluate contributions of different dissociation channels considered. It was shown that nitrogen dissociation in the stationary N2 discharge is mostly provided by direct ekectron impact via exciatation of the pre-dissociative states N2* from the vibrationally excited nitrogen molecules N2(X,v). Acknowledgements: This work was supported by RFBR Grant No. 17-52-16001.