Single crystal electron spin resonance spectrum of the p-tolyl radical: hyperfine tensors of ortho protons

Abstract

Single crystals of toluene-p-sulphonic acid (p-TSA) were γ-irradiated at room temperature. The radicals produced were examined by e.s.r. spectroscopy and the angular dependence of the spectrum investigated. One of the species produced gives an unresolved, orientation independent band, while the other shows a detectably orientation dependent hyperfine structure. By thermal annealing the unresolved signal disappears allowing a study of the remaining spectrum, which is assigned to the p-tolyl radical. The hyperfine structure due to the ortho protons of this radical is described.