Electron paramagnetic resonance of radiation damage of ?-irradiated diethylmalonic acid

It has been found that gamma-irradiation produces the CH3CH2C(COOH)(2) and (CH3CH2)(2)CCOOH radicals in this compound and gamma-irradiation damage centers in (CH3CH2)(2)C(COOH)(2) single crystal has been investigated by electron paramagnetic resonance (EPR) spectroscopy at room temperature. The crystals of diethylmalonic acid have been investigated at 295 K and analyzed for different orientations of the crystal in the magnetic field. The hyperfine coupling constants of the four hydrogens of the two methylene groups were found to be not equivalent. The g factor and the hyperfine constants for H atoms, as 3.0 mT, 1.80 mT, 0.59 mT and g = 2.0032, were found to be nearly isotropic. These results were compared with the earlier studies in malonic acid and derivatives radicals and discussed. (C) 2007 Elsevier B.V. All rights reserved.