An XAFS study of the local structure of Eu3+ ions in glasses prepared by a levitation technique

The local structure around Eu3+ ions in Eu-doped glasses prepared by a levitation technique was analyzed by X-ray absorption fine structure spectroscopy. The X-ray absorption near edge structure spectra demonstrated that Eu3+ ions in Al2O3–SiO2 binary glasses were partly reduced during high-temperature melting. Extended X-ray absorption fine structure spectra indicated that in La2O3–Nb2O5, La2O3–Al2O3, and La2O3–TiO2 glasses that contained a large amount of La2O3, the bond lengths between Eu and O were distributed from 2.34 to 2.39 Å. The coordinated polyhedra around the Eu ions could be fitted to a single coordination sphere. It was found that the bond lengths tend to become shorter as the optical basicity of the glass increases. In the Al2O3–SiO2 glasses without any network modifiers, the local structure around the Eu was more complex, leading to the broader first correlation peak of radial structure function.