Infrared emission by active nitrogen I. The kinetic behaviour of N2(B'3∑-u)

Emission from levels v = 0-8 of N2(B'3∑-u) has been studied in active nitrogen by using nitrogen, argon and helium carriers. Except at low pressures, the population of each level N2(B', v) closely follows that of the adjacent level N2(B, v+4). N2(B') is populated by collision induced transitions from N2(B), with N2 the rate constant for N2(B,v = 11) to N 2(B',v = 7) is 4.7 x 10-12 cm3 molecule-1 s-1 and the total rate constant for quenching this state (which is mainly to N2(B)) is 6 x 10-12 cm3 molecule-1 s-1. Vibrational relaxation of N2(B') by N2 or Ar is unimportant. The transition moment of N2(B'3∑-u -> B3IIg) is close to that of N2(B3IIg-> A3∑+u) having RE(0, 0) = 1.7D.