THE SPECTRUM AND STRUCTURE OF THE FREE NCN RADICAL

Abstract

A complicated group of bands near 3290 Å appearing in absorption in the flash photolysis of diazomethane has been photographed at high resolution. A detailed rotational analysis of the strongest (0–0) band has shown that the spectrum arises from a ³Π_u(inv)– transition of the linear symmetric molecule NCN. The triplet fine structures have been resolved for both upper and lower states. The main molecular constants are found to be: The upper state shows evidence of Renner-Teller interaction, with a splitting parameter εω₂ = −85.7 cm⁻¹. None of the vibration frequencies of the molecule could be determined.