ESR and ENDOR measurements on glyclglycine HNO3 x irradiated at 4.2°K

ESR and ENDOR spectroscopy were used to observe the effect of ionizing radiation on single crystals of glycylglycine HNO₃ x irradiated at 4.2°K. The paramagnetic species ${\mathrm{NO}}_3^{\text{2−}}$ and NO₂ are formed. The N¹⁴ hyperfine and quadrupole coupling tensors were determined from the ENDOR spectra, and the g tensors were determined from ESR spectra for both species. A mechanism of NO₂ formation is suggested which involves transfer of a proton to ${\mathrm{NO}}_3^{\text{2−}}$ and formation of OH⁻.