ESR AND OPTICAL-ABSORPTION STUDIES OF MN2+ IONS DOPED SILICA AND GERMANIA GELS

The results of an investigation of the structure of Mn2+ ions in silic a and germania sol-gels using DTA, ESR and optical absorption techniqu es are reported. ESR spectra of Mn2+ doped silica and germania gels at 303 K have a well resolved hyperfine structure of six lines spread ov er a region of about 50 mT centered at g = 2.003 +/- 0.001. The optica l absorption spectrum for silica gels heat treated at 573 K shows band s characteristic of Mn2+ ions in an octahedral symmetry.