Electron Spin Resonance of the Triplet State of a Photochemical Oxidation Product of Crystalline Durene

An optical method of detection of electron spin resonance of metastable states has permitted the investigation of the triplet entity responsible for the blue component in the phosphorescence of purified crystalline durene. This entity has fine structure parametersand D/hc = ±(0.335 ± 0.003) cm−1E/hc = ∓ (0.043 ± 0.002) cm−1The principal axes of the fine structure tensor and the magnitudes of its principal values are consistent with Sponer and Kanda's attribution of this phosphorescence to an aldehydic photo-oxidation product of the durene molecule.