Structural Characterization of KLa2F7 and Spectroscopic Study of KLa2F7 : Nd3+

The crystal structure of the fluoride KLa 2 F 7 was refined at 10 K by the Rietveld method using neutron powder diffraction data. KLa 2 F 7 is cubic, a = 5.918(1) A, space group Fm3m. The structure derives from that of an anion excess fluorite-type compound. The neodymium fluorescence decay kinetic in the doped compound KLa 2 F 7 :Nd 3+ was studied. The lifetime value of the 4 F 3/2 2 excited state is close to 470 μs The kinetic microparameters CDA related to the cross-relaxation and C DD related to the energy migration probabilities, were found to be equal to 3.6 x 10 -40 and 0.94 x 10 -40 cm 6 s -1 , respectively. Three broad bands, for which the relative intensities depend on the Nd 3+ concentration, were identified on the spectra in the region of the 4 I 9/2 → 2 P 1/2 transition. Therefore, at least three different sites for Nd 3+ ions exist in KLa 2 F 7 .