Endor study of bituminous coal Available to Purchase

This project is intended to develop an effective method for characterizing coal which will supplement the existing characterizing methods. We are using the new electron‐nuclear‐double‐resonance (Negative ENDOR) technique which we have developed for the past six years. The unique effectiveness of this method has already been confirmed: three different ingredients of bituminous coal give entirely different ENDOR signals, although the electron spin resonance (ESR) signals from these samples are practically identical in both line shape and intensity. These ENDOR signals were further studied in the present investigation. It was found that the signal from the vitrain ingredient increased dramatically with increasing intensity of the radio frequency (RF) field. This result is quite different from the case of the radiation‐produced radicals, for which the signal intensity saturates at a high RF field. It was also shown that the shape of the signal depended on microwave power. In the case of the clarain ingredient, the ENDOR signal suggested that no significant exchange interaction exists between the radicals. On the basis of these results, some characteristics of the radicals in each ingredient discussed have been determined, and will be presented.