Energy Transfer from N₂(v) to ClN₃ and a Kinetic Model for the Chain Decomposition of Chlorine Azide

A number of experiments have been performed in an effort to better understand the photoinitiated chain decomposition of ClN 3 . Discharge-flow methods were used to determine the rate of energy exchange between vibrationally excited N 2 (a likely chain carrier) and ClN 3 . The rate constant for energy transfer from N 2 ( v =1) to ClN 3 was found to be (2.0 ± 1.0) × 10 -13 cm 3 s -1 at 300 K. This process is thought to excite the ν 2 mode in ClN 3 with the release of 281 cm -1 of excess energy. Experiments were also performed in which the decomposition of ClN 3 was initiated by photolysis with a pulsed KrF laser at 249 nm, with subsequent observation of the time dependence of the densities of ClN 3, electronically excited NCl(a 1 Δ), and vibrationally excited ClN 3 (ν 2 ). A kinetic model for the ClN 3 decomposition was assembled based on reactions with NCl(a 1 Δ) and N 2 (ν).