Population of N2 (B 3Πg) by N2 (A3Σu+) during the nitrogen afterglow

Abstract

The time dependence of the intensity of various emission bands during the decay period of plasmas produced in pure nitrogen was measured using the stationary afterglow method. Two processes involving the N2 (A3Σu+) metastable molecule were found to populate the N2 (B 3Πg) state during the nitrogen afterglow. The first process is the energy pooling reaction N2 (A3Σu+)+ N2 (A3Σu+) → N2 (B3Πg)+N2 (X1Σg+), which also populates the N2 (C 3Πu) and N2 (C′3Πu) states. An approximate value for the reaction rate constant for this process was found to be (1.1−0.5+2)× 10−9 cm3 sec−1 per molecule. Strong evidence was found that N2 (B 3Πg) is also populated by the reaction N2 (A3Σu+)+N2* (X)→N2 (A3Σu+, v′>7)+N2(X)→ N2 (B3Πg)+N2 (X), where N2* (X) is a vibrationally excited ground state nitrogen molecule. The population of the N2 (B 3Πg) energy state by recombination of nitrogen atoms was also observed.