Transition probabilities of europium in phosphate glasses

Abstract

Absorption, excitation, and emission spectra of europium have been measured in metaphosphate glasses, The oscillator strengths of the transitions of the 7Fo and 'F1 levels are calculated and compared with the values for aqueous solutions. The intensities and half-bandwidths of fluorescence from the SDo levels are compared with those of silicate glasses and aqueous solutions. The influence of the crystal fields of the glass 013 the hypersensitive AJ = 2 transition is discussed. The point symmetry of Eu in phosphate glass was found to be C,. The broadening of the spectral lines in glasses and aqueous solutions has been attributed to a multiplicity of sites with the same symmetry and various crystal field parameters.

Tuning Photoluminescence Response by Electric Field in Electrically Soft Ferroelectrics

“…1a, this line is asymmetrically broadened in unpoled NBT-6BT:Eu suggesting two closely spaced lines of nearly equal intensity (marked with an arrow). Earlier, extensive broadening of the 5 D 0  7 F 0 line have been reported in Eu doped calcium diborate, silicate, germinate and phosphate glasses due to a large number of sites of same local symmetry (C s ) but with slightly varying crystal field strengths [23,24]. In our case, the slightly different crystal field strengths can arise from the different local chemical environment around Eu +3 formed by different configurations of Na and Bi and Ba [25,26], along with their respective local polar displacements [27].…”

Surface Modification and Functionalization of Microporous Hybrid Material for Luminescence Sensing

“…[19] Here the R value is about 9.9, indicating that the local surrounding observed in our sample is highly asymmetric if taking into account that R value reported for europiumA C H T U N G T R E N N U N G (III) ions in aqueous solution, in which they are directly coordinated to 8-9 water molecules, is 0.43. [20] Coating the silica shell on microporous hybrid material 1 following the procedure reported in reference [6] produces the core-shell hybrid material 2. The formation of the silica shell was obsereved by SEM (Figure 2).…”

Inorganic ions in glasses and polycrystalline pellets as fluorescence standard reference materials

“…In a cube made of phosphate tetrahedra in which the phosphorus-oxygen distance is 1.57 A and the oxygen-oxygen distance is 2.56 A, the rare-earth oxygen distance is 2.22 A. It should be realized that in reality the symmetry is lower than cubic, and for the particular cases studied it was found to be of Cs symmetry Eu 3 + in phosphate glass, [40] and C2 for Tm3+ is phosphate and borate glasses [39]. As a result of this lower symmetry, forced electric dipole transitions become possible and absorption and fluorescence is observed.…”

“…,-- b = repulsion coefficient: r= distance between active ion and nearest anion; n=4 to 1O~_ It was shown in a series of papers by Reisfeld et al [36][37][38][39][40], that the behavior of rare earths in glasses is similar to that of rare earths in inorganic crystals of low symmetry except for inhomogeneous broadening of the spectra due to a multiplicity of rare-earth sites in glasses. According to our theory [39] a rare·earth ion occupies a center of a distorted cube comprised of four tetrahedra of borate, phosphate or silicate.…”