Mössbauer and Fluorescence Spectroscopic Study on the Local Environment around Trivalent Europium Ion in the Chlorofluorozirconate Glass System

Chemical bonding state and fluorescence properties of Eu 3+ ions in the ZrF 4 −BaF 2 glass system in which a part of the F - ions are successively substituted by Cl - ions have been investigated by means of 151 Eu-Mössbauer and Eu 3+ -fluorescence spectroscopies. Mössbauer spectra indicated that Eu in the chlorofluorozirconate glasses exists only as the +3 oxidation state. Isomer shift of 151 Eu 3+ increased with an increasing amount of Cl - . This change corresponded to the intensity of the hypersensitive 5 D 0 → 7 F 2 transition in Eu 3+ fluorescence. This suggests that the intensity of the hypersensitive 5 D 0 → 7 F 2 transition depends on the density of 6s electrons at the Eu nucleus. The intensity of the 5 D 0 → 7 F 0 transition increases with increasing Cl - amount. Ligand field strength around Eu 3+ and the inhomogeneous line width of Eu 3+ fluorescence calculated from fluorescence spectra of the 5 D 0 → 7 F 0 transition decreased with increasing amount of Cl - . These results revealed that even a small amount of Cl - substitution greatly changes the local environments around Eu 3+ .