Electron spin resonance of γ-irradiated taurine

The 9.5 GHz electron spin resonance (e.s.r.) spectra of single crystal and powder samples of γ-irradiated taurine, [Formula: see text], have been recorded. Overlapping spectra from three distinct radicals are present. The first of these is the species SO 3 − with an isotropic g-value of 2.0035 and a 33 S hyperfine coupling tensor with principal values 135.2, 99.2, and 97.9 G. The second radical is a π-electron species with the unpaired electron mainly on carbon and exhibiting hyperfine interaction from at least four protons, probably [Formula: see text] and with principal g-values 2.0021, 2.0027, and 2.0034. The third radical has principal g-values 2.0024, 2.0056, and 2.0097 and principal values of the 33 S hyperfine tensor of 49.6, 9.1, and 1.2 G. The proposed structure for this radical is [Formula: see text]