Deduction of relaxation parameters from saturation in non-uniformly broadened ESR lines

A mode with noninteracting spin packets is used to calculate the saturation curves of lines with Gaussian and Lorenzian shapes, provided that the steady magnetic field is modulated at a low frequency. Curves are given that allow deduction of the width of the spin packets from the observed saturation curves. Tests are reported for the radicals produced by γ-rays in d, l-alanine, glycine, and phenol; the relaxation times T2 are found to be respectively 2·10−8, 3.8·10−8, and 2.7·10−8 sec. In the first two cases T2 agrees roughly with the width of the spin packets calculated from the radical concentrations.