Matrix Isolation Study of the Photolysis of Cyanogen Azide. The Infrared and Ultraviolet Spectra of the Free Radical NCN

Abstract

The infrared and ultraviolet absorption spectra of the free radical NCN have been observed following photolysis at wavelengths longer than 2800 Å of cyanogen azide isolated in argon, nitrogen, carbon monoxide, and carbon dioxide matrices. The infrared‐active vibrational fundamentals of NCN appear at 423 and at 1475 cm⁻¹. Isotopic studies are consistent with this identification. The force constants and thermodynamic properties of NCN have been estimated. Two ultraviolet absorption systems are associated with NCN. The first of these, previously reported, lies near 3290 Å. The second system is comprised of a progression of bands spaced at intervals of approximately 1045 cm⁻¹, lying between 3000 and 2400 Å. The nature of this second transition is discussed. At wavelengths longer than 2800 Å both cyanogen azide and NCN have been found to photolyze with the production of carbon atoms. The nature of the new features observed in the infrared and ultraviolet spectral regions after photolysis with short‐wavelength radiation is considered.