Electron paramagnetic resonance study of the paramagnetic centers in gamma-irradiated oxalic acid dihydrate single crystal

Highlights: • The ionized radiation effect of oxalic acid dihydrate single crystal was investigated by EPR method. • It was observed that two biradicals were formed. • It was observed that O–H single bonds were broken and formed paramagnetic centers. • Hydrogen atoms in the water molecule produced hyperfine structure splittings. The Electron Paramagnetic Resonance (EPR) spectra of the radicals produced by γ-irradiation of a single crystal of oxalic acid dihydrate (C₂H₆O₆) have been reported. The EPR spectra of gamma-irradiated single crystals of oxalic acid dihydrate have been studied for different orientations of crystals in a magnetic field. As a result of studies carried out along three axes, it has been determined that there are two biradicals. The EPR spectra have been investigated at temperatures between 125 and 450 K. The spectra have been found to be temperature independent. The g values of the radiation damage centers observed in oxalic acid dihydrate acid single crystal and the hyperfine structure constants of the free electron with nearby protons have been obtained from the single crystal EPR analysis.