Hyperfine Structure in the EPR Spectrum of the Manganous Ion in Frozen Solutions

EPR spectra of 10—3M MnCl2 were studied in various solutions at —180°C, and in 12M HCl or methanol the hyperfine structure was very similar. This hyperfine structure was then studied with respect to a changing Cl—/Mn++ ratio by addition of LiCl or HCl to the MnCl2 solution. These spectra may be explained in terms of a spin Hamiltonian by considering only the M = ½↔M = —½ transitions, and the occurrence of forbidden Δm = ±1 transitions.