Analysis of the Crystal Structure and Optical Spectra of Stoichiometric SmOF

Abstract

The relationship between the crystal structure and the crystal field (CF) effect was studied in the hexagonal samarium oxyfluoride (SmOF). The crystal structure of SmOF was refined with the Rietveld method from the X-ray powder diffraction data in the range of 6.5 < 2θ < 121.4°. The Ar + ion laser excited luminescence spectra of the Sm 3+ ion (4f 5 electron configuration) doped LaOF and GdOF were recorded at 77 and 300 K between 500 and 800 nm. The absorption spectra between 295 and 2055 nm were measured at selected temperatures between 9 and 300 K using the pure hexagonal SmOF. Analysis of the spectra according to the C 3V symmetry for the Sm 3+ site in rare earth oxyfluoride (REOF) yielded 195 Stark components out of the total 1001. For the energy level simulation, a model of 20 adjustable parameters was used including the Racah, Trees, and Judd parameters, the spin-orbit coupling constant (ζ 4f ), and, and B 6 6 CF parameters. The experimental energy level scheme was well reproduced with a root mean square deviation equal to 17 cm -1 . The CF parameter set was found to be consistent with those for other RE 3+ ions in REOF matrices. Structural data were used to calculate the CF parameters by a modified point charge model. The calculated second-range contribution was too high, whereas the fourth-and sixth-rank contributions were close to the experimental ones. The experimental and calculated CF parameters indicate only slight distortion from the ideal fluorite-type cubic structure.

Influence of the chemical environment on the electronic structure and spectroscopic properties of Er3+ doped Cs3Lu2Cl9, Cs3Lu2Br9, and Cs3Y2I9

“…[1][2][3][4][5][6][7][8][9][10][11] Er 3ϩ has received particular attention, mainly because of its potential for near-infrared ͑NIR͒ to visible ͑VIS͒ upconversion. The ultimate aim of such calculations is the prediction of the energy-level structure of new compounds or, for a given system, the prediction of relative intensities for potential laser transitions or the efficiency of potential upconversion mechanisms.…”

Bifunctional Europium for Operando Catalyst Thermometry in an Exothermic Chemical Reaction

“…The bifunctional EuOCl catalyst material was synthesized (see Supporting Information section 1 for more experimental details) in the desired EuOCl crystal phase (Figure S3A) with an irregularly shaped morphology (Figure S3B) [25, 27, 32] . The excitation of EuOCl with 375 nm light yielded sharp emissions (Figure S4), which could all be assigned according to the energy diagram of Eu 3+ (Figure 1A) [33, 34] . The EuOCl catalyst material showed temperature‐dependent emission from 400 to 550 °C (Figure 1B).…”

NIR-to-visible and NIR-to-NIR upconversion in lanthanide doped nanocrystalline GdOF with trigonal structure

“…00-050-0569 of the PDF-4+2008 database. A Rietveld refinement [18,19] exploiting the trigonal structural model proposed by Hölsa et al [20] for SmOF, was carried out on the powder pattern for the Tm 3+ /Yb 3+ codoped oxyfluoride sample (see Fig. 1).…”