Intensity of allowed and forbidden electron spin resonance lines of Mn2+ in tremolite

Abstract

The angular variation of the intensities of the allowed and forbidden (Δm = ±1) electron spin resonance lines of Mn2+ impurities in tremolite, 2(H2Ca2Mg5(SiO3)8), was studied at room temperature and in the 9.2-GHz microwave frequency range. The crystalline electric field for the magnetic complex of Mn2+ in tremolite has orthorhombic symmetry, and this causes the line intensities to vary asymmetrically between the z and y magnetic axes. The experimental measurement of these intensities is in good agreement with the theoretical calculations of Bir (1964). Bir's theory has been used with success previously by others for ions in the higher-symmetry axial and cubic crystalline electric fields.