Dispersed emission spectrum of NH2 (Ã 2A1) in the ultraviolet laser photolysis of HN3 and the mechanism of formation

The chemiluminiscent reaction following the ultraviolet (266 nm) photolysis of HN 3 has been studied. A dispersed emission spectrum was recorded, which is, to the best of our knowledge, the first direct identification of the origin of the chemiluminescence. The emissive species was assigned to vibronically excited NH 2 . The observed vibrational distribution in the NH 2 (A 2 A 1 ) was not consistent with the reaction mechanism previously suggested (NH(a 1 Δ, v = 0) + HN 3 ). A modified mechanism including vibrationally excited NH(a 1 Δ) has been proposed on the basis of energetics and kinetics in terms of the emission.