176 resultados para BaFI:Eu2
Resumo:
The reduction of RE3+ to RE2+ (RE=Eu, Sm and Tm) in SrB6O10 prepared in air by high-temperature solid state reaction was observed. The luminescent properties of Eu2+ and Tm2+ show f-d transition and Sm2+ shows f-f transition at room temperature. Three crystallographic sites for Sm2+ in matrix are available. Vibronic transition of D-5(0)-F-7(0) of Sm2+ was studied. The coupled phonon energy about 108 cm(-1), was determined: from the vibronic transition. Due to the thermal population from D-5(0) level, (D1-FJ)-D-5-F-7 (J=0, 1, 2) transitions of Sm2+ were observed at room temperature. A charge compensation mechanism is proposed as a possible explanation.
Resumo:
MAl2O4 Eu2+RE3+(M=Mg,Ca,Sr,Ba;RE=Y,La,Ce,Pr,Nd,Sm,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu).Eu2+4f-5d.Re3+,.RE3+,MAl2O4 Eu2+RE3+RE3+.,,X-,,,
Resumo:
Eu2+MMgAl10O17M0.10nm-Al2O3Eu2+Ca2+-Al2O3Mg2+Al3+Eu2+dfEu3+-Al2O3Eu2+-Al2O3Mg2+Al3+Eu2+dfffEu3+-Al2O3Eu2+ffEu3+-Al2O3-Al2O3Eu2+ffdf
Resumo:
KZnF3Ce3+Eu2+Ce3+Eu2+Ce3+Eu2+Ce3+Eu2+f-f.
Resumo:
BaMgAl10O17:Eu2BuMgAl10O17Eu2,Eu2.
Resumo:
NaEu2Na1xMgAl11xO17NaAl2O3Na1672xBaxAl1033O17x030x030NaAl2O3x030BaAl2O3Eu2NaAl2O3Eu2Al2O3Na067Ba050Mg067Al1033O17Eu2005mol.
Resumo:
-Al2O3Eu2+Eu2+-Al2O3
Resumo:
Eu2+Eu2+.
Resumo:
Eu2+Li--Al2O3Eu2+BaMgAl10O17-Al2O3Li--Al2O3Al3+Li+Eu2+Li--Al2O3
Resumo:
The reduction of Eu3+ to Eu2+ in SrB6O10 prepared in air by a high-temperature solid state reaction was studied. The luminescent properties of Eu2+ in this matrix show f-d broad band emission peaking at about 386 and 432 nm at room temperature. A charge compensation mechanism is proposed as a possible explanation. The luminescence of Eu3+ with f-f transitions was studied in this sample and reflected that the Eu3+ ion occupied a site with non-centro-symmetry. The ESR spectrum was used to detect the existence of Eu2+ in the samples. (C) 1998 Elsevier Science S.A.
Resumo:
Single crystal of KZnF3 : Eu3+ has been grown by means of Bridgman-Stockbarger technique in Ar atmosphere, The emission and excitation spectra of europium ion were measured, The results show that a small amount of Eu2+ exists in the crystal, The existence of Eu2+ ions was also confirmed by ESR data, The valence change of Eu ions during the crystal growth is due to unequivalent substitution of Eu3+ ions for the lattice ions. The sites possibly occupied by Eu ions in this crystal were also discussed.
Resumo:
Luminescence of europium (III), europium(II) and terbium(III) has been observed in Ba-3(PO4)(2):Eu, Tb phosphors which are synthesized in air atmosphere. The valence state of europium is influenced by amount of terbium. It is notable that the relative intensity of the emission spectra peaks corresponding to Eu2+ is increased if the amount of Tb3+ is increased. These phenomena can be explained by an electron transfer mechanism. We predict a new kind of two-rare-earth codoped trichromatic phosphors in Ba-3(PO4)(2) matrix.
Resumo:
In this paper, the luminescence properties of SrB4O7: xEu, yTb phosphors were investigated. The SrB4O7: xEu, yTb phosphors were first synthesized in air atmosphere, and the emission spectra of Eu2+, Eu3+ and Tb3+ ions have been observed in phosphors. We found that the relative intensity of the emission of Eu2+ ion in the same matrix are increased when Tb3+ is incorporated in SrB4O7:Eu phosphor. So the valence state of europium is influenced by terbium. These phenomena can be explained using an electron transfer theory.
Resumo:
KCa F3 Eu2 + Eu2 + Eu2 + Tb3 + , Eu2 +
