Optical absorption and emission spectra of Eu'+ in Ba(PO3)2, Zn(PO3)2, and Pb(PO3)2 glasses are reported. Judd-Ofelt intensity parameters for f ftran-sitions were derived from the integrated absorption spectra and used to calculate the spontaneous emission probabilities from the Do state. Fluorescence-line-narrowed emission excited by the 'Do~'Fo transition was used to study local structure around the Eu'+ ion. A phenomenologica1 crystal-field analysis was conducted using C2, symmetry, and it was found that the sites occupied by Eu'+ in the glasses are adequately described by Brecher and Riseberg's model. The influence of the network modifier ions (Ba, Zn, and Pb) on the major crystal-field parameter ratio (B»/B20 and B4&/B40) is discussed. Furthermore, it was shown that the network modifier ions affect the properties of the Eu -0 bond, and, consequently, the crystal-field strength.

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The fluorescence of Eu3+ doped lanthanum–calcium–zirconium–silicon borate ceramic was studied at 77 and 300 K using laser excited site selective spectroscopy. The fluorescence spectrum excited at 514.532 nm reveals the presence of three distinct sites for Eu3+. The sites were assigned to Eu3+ substituting for lanthanum in a ninefold coordination site in LaBO3 and Eu3+ substituting for Ca2+ in six- and sevenfold coordination sites in Ca2B2O5. To assign the spectra to the definite sites a phenomenological crystal field analysis was conducted, using C2v symmetry. The crystal field for Eu3+ in Ca2B2O5 was found to be dominated by electrostatic effects. The large 7F1 level splitting and the value of the B20 parameter support the concept of strong ionic bonding between europium and oxygen in Ca2B2O5.

An investigation of low-frequency inelastic scattering (LOFIS) and pre-resonant Raman spectroscopy has revealed the role of the modifying cations, Ba2+, Zn2+ and Pb2+ on the bonding properties of the Eu-O bond in Ba(PO3)2, Zn(PO3)2, and Pb(PO3)2 glasses. Analysis of the results has shown that the electronegative character of the Pb2+ ions and the ionic radii of the Ba2+ and Zn2+ ions play a major role in the short-range order of the metaphosphate glasses. Furthermore, it was shown, using LOFIS, the influence of the modifying cations on the size distribution of the structural units found in the metaphosphate glasses.

An investigation of low-frequency inelastic scattering and Auorescence line narrowing has revealed the role of Eu + in the nucleation process. Analysis of the results has shown that the Eu'+ accelerates nucleation; however, it is not incorporated into the microcrystalline phase. Polarization studies have shown that the nucleating agents Eu + and Cr' modify the size of the microcrystallites and the symmetry of the vibrational eigenmodes. The results show that the vibrational eigenmodes for the Cr'+-doped glass are mainly breathing modes, whereas for the Eu' -doped and undoped glass they are spheroidal and/or torsional modes.