ESR Spectra of Exchange-Coupled Mn²⁺ Ions in ZnS and CdS

The ESR spectra of the powder samples of cubic ZnS:Mn, hexagonal ZnS:Mn, and CdS:Mn are treated theoretically for the case where the exchange interaction exists between the Mn 2+ ions. The comparison of the calculation with experiments indicates that, for a pair of Mn 2+ ions, the resonance spectra are well described by the spin Hamiltonian in which the Zeeman, hyperfine, and isotropic exchange terms are included, but anisotropic interaction terms are neglected; the g -factor and the hyperfine constant are isotropic and the same for each of exchange-coupled Mn 2+ ions, and the cxchange interaction is of the Heisenberg type. Also, a discussion is given on the case of a cluster of three or more Mn 2+ ions.