?-Radiation Induced Color Centers in Anthracene

Abstract

The effects of γ-irradiation on pure anthracene have been investigated by optical absorption and electron paramagnetic resonance (EPR) measurements. It is found that the optical absorption peaks which are produced by the radiation at 30°C are stable at 30°C but increase upon annealing up to 140°C; the most prominent of these being at 6060 Å and 5350 Å. EPR signals arising from irradiation are stable to 140°C but do not grow between 30°C and 140°C. Both optical density and EPR signals decrease upon annealing above 190°C. A model is proposed to explain the nature of the EPR signals based upon cross-linking of the anthracene molecules.