Azide mechanisms for the production of NCl metastables

The production of both the b 1 Σ + and a 1 Δ states of NCl has been observed from the reaction of HN 3 with flowing streams of Cl and F atoms. The results suggest that a two‐step reaction sequence is responsible for the production of excited NCl, as follows:The rate contant (all products) for the first step is k (F + HN 3 ) > 1 × 10 −11 cm 3 /molecule sec. Comparison of this value to results obtained in a previous study of the F + HN 3 system yields a value k (F + N 3 ) = 2 × 10 −12 cm 3 /molecule sec. The rate constant for the reaction of chlorine atoms with HN 3 was determined to be k (Cl + HN 3 ) 1 × 10 −12 cm 3 /molecule sec. The difference between the Cl + HN 3 and F + HN 3 rates is interpreted in terms of an addition–elimination mechanism.