ENDOR study of the radical created by gamma irradiation at room temperature in the 1,2,4-triazole crystal

The complete ENDOR study of the radical induced by gamma irradiation at room temperature of single crystals of 1,2,4-triazole enables us, by analysis of all the measured proton hyperfine tensors, to determine its exact nature. It corresponds to a π radical formed by the addition of one hydrogen atom to a carbon of the ring. An unconventional but satisfying determination of the map of the spin density distribution in the radical has been carried out using bascially the theoretical reconstitutions of the dipolar tensors. These results are discussed and compared with those of molecular orbital calculations.