Infrared emission by active nitrogen I. The kinetic behaviour of N 2 (B' 3 ∑ - u )

Abstract

Emission from levels v = 0-8 of N 2 (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 N 2 (B', v ) closely follows that of the adjacent level N 2 (B, v +4). N 2 (B') is populated by collision induced transitions from N 2 (B), with N 2 the rate constant for N 2 (B, v = 11) to N 2 (B', v = 7) is 4.7 x 10 -12 cm 3 molecule -1 s -1 and the total rate constant for quenching this state (which is mainly to N 2 (B)) is 6 x 10 -12 cm 3 molecule -1 s -1 . Vibrational relaxation of N 2 (B') by N 2 or Ar is unimportant. The transition moment of N 2 (B' 3 ∑ - u -> B 3 II g ) is close to that of N 2 (B 3 II g -> A 3 ∑ + u ) having R E (0, 0) = 1.7 D .