Kinetics of chemiluminescent reactions of the gaseous azide radical

Abstract

The azide (N₃) radical has been detected as a product of the rapid reaction, [graphic ommitted]; k₁ > 10^11.7 cm³ mol^–1 s^–1 at 300 K. Atomic Cl, Br, O and N react with N₃ forming electronically and vibrationally excited NX^* molecules, which emit chemiluminescence, X + N₃→ NX^*+ N₂. Measurements of energy transfer to the product NX^* molecules formed (NCl(b¹∑⁺), NBr(A¹∑⁺), NO(A²∑⁺ and B²Π), N₂(B³Π_g)), give values for the standard heats of formation of N₃, NCl, and NBr: ΔH°_f(300)(N₃)= 4.3 ± 0.1 eV; ΔH°_f(300)(NCl)= 2.7 ± 0.1 eV; ΔH°_f(300)(NBr) > 2.09 eV. A number of new bands of the ¹∑⁺→X³∑^– systems of NBr and NCl was identified, and vibrational constants for NCl are reported.