5d-4f luminescence of Ce3, Gd3 and Lu3 in LiCaAlF6

The emission and excitation spectra as well as decay kinetics of luminescence due to 5d4f transitions in Ce3, Gd3 and Lu3 ions doped into LiCaAlF6 crystals have been analyzed with high spectral and time resolution using synchrotron radiation for excitation. The rich fine structure originating from electronic origins of transitions and their phonon replica has been well resolved and identified. Experimental data are compared with the spectra simulated in the framework of the semiphenomenological models of the crystal field and the crystal lattice dynamics. © 2011 Elsevier B.V. All rights reserved

Location of the Energy Levels of the Rare-Earth Ion in BaF2 and CdF2

The location of the energy levels of rare-earth (RE) elements in the energy band diagram of BaF2 and CdF2 crystals is determined. The role of RE3+ and RE2+ ions in the capture of charge carriers, luminescence, and the formation of radiation defects is evaluated. It is shown that the substantial difference in the luminescence properties of BaF2:RE and CdF2:RE is associated with the location of the excited energy levels in the band diagram of the crystals

Vacuum-ultraviolet 5d-4f luminescence of Gd3+ and Lu3+ ions in fluoride matrices

The VUV 4 f n-1 5d-4 f n luminescence and luminescence excitation spectra of Gd3+ (n=7) in LiGdF4, GdF3, LiYF4: Gd3+, and YF3: Gd3+, and of Lu3+ (n=14) in LiLuF4, LuF3, and LiYF4: Lu3+ have been analyzed with high spectral resolution. In systems with intermediate electron-phonon coupling, zero-phonon lines, and phonon sidebands were observed. The excitation spectra of dilute systems exhibit rich fine structure originating from electronic origins of transitions and their phonon replica. Theoretical calculations explicitly taking into account a microscopic model of the crystal field and the crystal lattice vibrational spectra agree well with experimental data and are the basis for a safe analysis of the spectra. © 2007 The American Physical Society

Luminescence of the SrCl2:PrSrCl_{2}:Pr crystals under high-energy excitation

The present research was carried out in order to elucidate the mechanisms of energy transfer from the crystal lattice to Pr3+ ions in SrCl2. The luminescence excitation and emission spectra as well as luminescence kinetics of the SrCl2:Pr single crystals containing 0.2 mol% Pr were investigated at 300 and 10 K using the vacuum ultraviolet (VUV) synchrotron radiation. The X-ray excited luminescence spectra of the SrCl2:Pr (CPr=0.2 and 0.5 mol%) and SrCl2:Pr, K (CPr=1.5 mol%; CK=1.5 mol%) crystals were studied at 294 and 80 K. Under optical excitation of the samples in the Pr3+ absorption bands, there were observed five fast ultraviolet emissions assigned to the 4f15d→4f2 transitions, and two long-wave bands corresponding to the f–f transitions. Furthermore, the intrinsic emission bands of SrCl2 were observed at 10 K. The X-ray excited luminescence spectrum of the SrCl2:Pr crystal containing 0.2 mol% Pr, besides intrinsic emission band near 400 nm, has got a long-wave band at about 490 nm of the Pr3+ centers. There were not observed any emission bands of the Pr3+ centers corresponding to the 4f15d–4f2 transitions in the X-ray excited luminescence spectrum of the SrCl2:Pr crystal. The possible mechanisms of energy transfer from the SrCl2 matrix to the Pr3+ centers are discussed