A STUDY BY EMISSION-SPECTROSCOPY OF THE N-2 ACTIVE SPECIES IN PULSED DC DISCHARGES

From the optical emission of N-2 and N-2(+) radiative states in the ne gative glow of N-2 DC pulsed discharges at pressures 1-4 Torr (133-532 Pa) and current densities 1-6 mA cm(-2), it has been determined that the vibrational excitation of the N-2 state deviates from a Boltzmann distribution and strong intensities of the N-2 second positive system (especially from v = 1) were also observed in the afterglow. Such stro ng emission is interpreted in terms of the growing of the N-2(X, v) vi brational distribution in the post-discharge region as the gas tempera ture is reduced. The N-2(+)(B-2 Sigma(u)(+)) states are mainly produce d by electron collisions on N-2(+)(X) ions under discharge conditions and quickly disappear in the afterglow as a result of N-2(+)-electron recombination.