INTERPRETATION OF MN2-SPECTRA IN DISORDERED MATERIALS( EPR)

It is interesting to be able to estimate the values of the zero-field splitting parameters D and E appearing in the spin Hamiltonian of the Mn2+ ion in disordered materials, such as glass and polycrystalline sa mples. Since the electronic spin of the Mn2+ ion is 5/2 (>1/2), it is able to interact with the crystalline electric field of the environmen t to provide information on its surroundings. The present work attempt s to interpret the intensities and positions of both the allowed and h yperfine forbidden EPR lines of the Mn2+ ion in disordered materials. First, a discussion is presented of the analytical expressions for the intensities and positions of the EPR lines in a monocrystal, which ar e then exploited by averaging to describe the expected behavior in dis ordered materials in order to estimate the values of the parameters D and E. The discussion is thereafter generalized to use computer simula tions to generate Mn2+ EPR spectra in glassy and polycrystalline media . The effects of distribution of D and E parameters and expected singu larities in Mn2+ EPR spectra on the resulting EPR spectra in disordere d materials are considered. Some published results are included to ill ustrate the application of the techniques described in this paper.