N(2D) in nitrogen afterglow

Homogeneous inverse predissociation in the N2(C 3Πu, v=4) state was investigated, in pure nitrogen afterglow, as a diagnostic tool for N(2D) density measurement. Vibrational distribution of N2(C 3Πu) was analysed along the afterglow employing emissions of the second positive system. For nitrogen afterglow with pressure ranging from 3.0 to 9.0 Torr, current between 20 and 50 mA and flux from 300 to 950 sccm, [N(2D)] was found to vary from 3% to 6% of [N(4S)].