Kinetics of the (A³Sigmau⁺, v=0) state of N₂in the near afterglow of a nitrogen pulsed discharge

The absolute densities of the nitrogen metastable molecules N 2 (A 3 Sigma u + , v=0) were measured as a function of time using a high resolution laser absorption within the first positive system (B 3 Pi g (v ' =2) from A 3 Sigma u + (v " =0)) in a stationary afterglow of the pure nitrogen pulsed electric discharge. The experiments were performed at various pressures (0.25-1.25 Torr), discharge currents (0.4-1.3 A) and pulse lengths (5-30 mu s). The lifetimes and populations are in the range 100-470 mu s and (0.3-2.7)*10 12 cm -3 respectively. The postulated kinetic model describes the measured lifetimes within an experimental error. The model takes into consideration the loss of N 2 (A) metastables due to energy pooling, quenching by nitrogen atoms and diffusion to the walls. Calculations of dissociation rates and nitrogen atom densities are based on the vibrational excitation of the ground electronic state N 2 (X).