IDENTIFICATION OF RADICAL STRUCTURE IN 2,4-DINITROCHLOROBENZENE SINGLE CRYSTAL BY EPR

The single crystals of the 2,4 dinitrochlorobenzen were grown by slow evaporation of concentrated ethanol solution. Some of these single crystals exposed to Co-60-gamma rays with dose rate of 0.880 kGy/h at room temperature for 48 and 72 h. The EPR spectra were recorded as a function of temperature and orientations of the single crystal in the magnetic field. The single crystal irradiated for 72 h was rotated in steps of 100 in three mutually perpendicular planes in the magnetic field. The ESR temperature measurements were performed between 120 K and 440 K. The spectra recorded were found to be dependent on the temperature and the orientations of the crystal. It was also detected that only a radical structure and color centers were occurred after irradiation. The average values of g and hyperfine coupling constants were calculated as follow: a(Na=Nb)=13.70 G, a(H1=H2)=8.95 G, a(H3)=7.06 G, g=2.0039.