title: Spectroscopic studies of the Eu3+ and Er3+ ions in the fluorozirconate LaZr2F11 matrix.
abstract: An investigation by optical spectroscopy of the Eu3+ and Er3+ active ions in the crystallized fluorozirconate matrix LaZr2F11 is presented. The 5D1-->7F0-5 emission lines of Eu3+ are used to extract the 7F0-5 energy scheme and the observed extinctions permit the deduction of irreducible representations (IRREPS) associated with corresponding sub-levels in the D2 symmetry. The crystal field analysis was carried out on a 387 x 387 basis set, comprising the 7F, 5D(1,2,3) 5F(1,2), 5G(1,2,3) and 3P(1,2,3,4,5,6) terms of the Eu3+ 4f6 configuration. The deviation and rms are 6.8 and 7.9 cm(-1), respectively for 38 levels and ten parameters. The experimental crystal field parameters are in good agreement with the ab-initio ones. Moreover, the relative intensities of the 5D0-->7F2,3,4 emissions are well reproduced by an 'ab-initio' calculation, except for three lines. The Er3+ ions introduced in LaZr2F11, microcrystals also lie in an unique crystallographic site. A total of 31 energy levels were recorded and the crystal field analysis led to 6.6 and 7.8 cm(-1) for the deviation and rms, respectively, for nine variable parameters taken into account. The experimental CF parameters for Er3+ and Eu3+ are very similar, which seems to show that the host lattice contracts around the smaller Er3+ ion. The informations given by both Eu3+ and Er3+ optical probes in LaZr2F11 are very consistent with the structure previously determined for the isotypic PrZr2F11 fluoride.
authors.affiliation: CEMES/CNRS, BP 4347, Toulouse, France. jdexpert@cemes.fr
authors.forename: J
authors.initials: J
authors.lastname: Dexpert-Ghys
authors.forename: S J
authors.initials: SJ
authors.lastname: Ribeiro
authors.forename: P
authors.initials: P
authors.lastname: Dugat
authors.forename: D
authors.initials: D
authors.lastname: Avignant
authors.forename: M D
authors.initials: MD
authors.lastname: Faucher
mesh_terms: D004871:Erbium / Q000737:chemistry*; D005063:Europium / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods; D015040:Zirconium / Q000737:chemistry*
chemical_list: C411137:lanthanum fluorozirconate; D005063:Europium; D004871:Erbium; D015040:Zirconium; D005459:Fluorides