Preparation of borates doped with divalent rare earth ions (RE2+) in air and spectroscopy of divalent rare earth ions (RE2+ = Sm, Eu, Tm, Yb)

The spectroscopic feature of divalent Sm2+, Eu2+, Tm2+ and Yb2+ is discussed in this paper. Especially the spectroscopic properties of some berates containing tetrahedral BO4 group such as SrB4O7, SrB6O10 and BaB8O13 doped with these divalent ions are reported. When the divalent alkaline earth ion in these berates is replaced partially by the above trivalent rare earth ion, the charge carried in the produced defects can be used as reductant to reduce the doped rare earth ion into divalent state at high temperature even in air. Therefore, a convenient and safe method is provided to prepared phosphors doped with these divalent rare earths.

Resonant two-photon cross-section calculations for transitions to 4f5d state in Pr3+: YAG using density matrix theory

The density matrix resonant two-photon absorption (TPA) theory is applied to a rare-earth ion-doped laser crystal. TPA cross sections for transitions from the ground state to the first 4f5d state in Pr3+:YAG are calculated. The results indicate the density matrix TPA theory is attractive in studying TPA in laser crystals. (C) 2000 Elsevier Science B.V. All rights reserved.

在空气下制备掺二价稀土的硼酸盐及二价稀土离子(RE~(2+)=Sm,Eu,Tm,Yb)的光谱特征

本文讨论了Sm2 + 、Eu2 + 、Tm2 + 、Yb2 + 等二价稀土离子的光谱特征 ,特别是在一些含四面体硼酸根的硼酸盐如SrB4 O7、SrB6 O10 和BaB8O13中它们的光谱性质。当以三价稀土离子取代化合物中的二价碱土离子时 ,利用不等价取代而产生的缺陷所带的电荷 ,可在高温的空气下使上述的稀土离子还原成二价 ,不需加入化学还原剂 ,从而提出了一个简便、安全的制备含二价稀土离子发光材料的方法

Tb~(3+)在YAG中的发光及Tb~(3+)与Tm~(3 +)间的能量传递

采用溶胶 -凝胶方法合成了系列化合物 (Y1 -x- yTbxTmy) 3Al5O1 2 ,研究了Tb3+在该化合物中的发光及其浓度对发光性质的影响 ,以及Tb3+与Tm3+间的能量传递现象。

Calculation of chemical bond parameters in RBa2Cu4O8(R = Dy,Ho,Er,Tm,Yb) and Y2Ba4Cu7O14.3

Chemical bond parameters in RBa2Cu4O8(R = Dy, Ho, Er, Tm, Yb) and Y2Ba4Cu7O14.3 were calculated by using complex chemical bond theory. The results indicated that the bond covalency in CuO chain was larger than that in CuO2 plane. For metal atoms, the bond covalency of five coordinated case was larger than that of six coordinated case.

Synthesis, crystal structure and reactivity of (2,4-C7H11)(2)Yb center dot DME

(2,4-C7H11)(2)Yb . DME was synthesized by the reaction of YbCl3 with K(2,4-C7H11)(2,4-dimethylpentadienyl potassium), and the single crystal X-ray diffraction showed that the complex exists in a cis- staggered conformation. Thf crystal of the compound belongs to the monoclinic space group P2(1)/n with a = 0.675 2 (1) nm, b = 1.490 6 (1) nm, c = 1.529 3 (2) nm, beta = 97.55 (2)degrees, V = 1.977 79 (4) nm(3), Z = 4, F(000) = 735.8 e, mu = 49.49 cm(-1), R = 0.033 and R-w = 0.032. The title complex can be used as a catalyst for the polymerization of methyl methacrylate (MMA).

RBa_2Cu_4O_8(R=Dy,Ho,Er,Tm,Yb)和Y_2Ba_4Cu_7O_(14.3)的化学键参数计算

使用复杂晶体上化学键理论计算了 RBa2 Cu4 O8(R=Dy,Ho,Er,Tm ,Yb)和 Y2 Ba4 Cu7O14 .3 的化学键参数 .结果表明 ,Cu O链上的 Cu O键共价性大于它们在 Cu O2 面的共价性 .当金属元素与氧形成五配位时 ,其共价性的数值大于这些元素在六配位时的情形

Luminescence of RE2+ (RE = Sm, Yb) in barium octoborate

The reduction process from trivalent to divalent state for Sm3+ and Yb3+ ions in barium berates (BaB8O13) prepared in air was observed. The luminescence properties of these divalent rare-earth ions were studied. Yb2+ shows an f-d broad emission band, due to the 4f(14) --> 4f(13)5d transition, while the Sm2+ ion shows an f --> f transition. From the spectra of Yb2+, and using the D-5(0) --> F-7(0) transition of Sm2+ as a structural probe, two crystallographic sites were found to be available for the cations in the host. Vibronic transitions of Sm2+ were observed at low temperature. BaB8O13 was found to be a good host for reducing the trivalent rare-earth ions to divalent state and to exhibit interesting spectroscopic properties,

Bond covalencies in R2BaCuO5 (R = Sm, Gd, Dy, Ho, Y, Er, Tm, Yb, Lu)

Bond covalencies in R2BaCuO5 (R = Sm, Gd, Dy, Ho, Y, Er, Tm, Yb, Lu) were calculated by means of a semiempirical method. This method is the generalization of the dielectric description theory of Phillips-Van Vechten-Levine-Tanaka scheme. The present paper presents the formula concerning the decomposing of complex crystals which are usually anisotropic systems into the sum of binary crystals which are isotropic systems. It can be seen that although the bond covalency is related to many physical quantities, it is mainly influenced by bond valence or bond charge, and a higher bond valence will produce higher bond covalency.

Structure and luminescent properties of YAG : Eu, Bi synthesized by sol-gel method

(Y1-xEux)(3)Al5O12 and (Y1-x-yEuxBiy)(3)Al5O12 were prepared by so-gel method. Their structures of the luminophor are similar to that of YAG, which is recorded on the ASTM card and belongs to a cubic system. The luminescent properties show that the reaction temperature of the current sol-gel method is in the range of 400-500 degrees C, which is lower than that of the conventional solid state reaction. The luminophors have the strongest emission intensity when the values of x and y are 0.06 and 0.013, respectively.

Synthesis of the first mono(cyclopentadienyl)lanthanide Schiff base complex bearing C-2-symmetric tetradentate ligand: crystal structure of [(eta(5)-C5H5)Yb(mu-OC20H20N2O)](2)(mu-THF)(THF)

Reaction of YbCl3 with 3 equimolar CpNa (Cp = cyclopentadienide) in THF, followed by treatment with trans-(+/-)-N,N'-bis(salicylidene)-1,2-cyclohexanediamine led to the isolation of first mono(cyclopentadienyl) lanthanide Schiff base complex, [(eta(5)-C5H5)Yb(mu-OC20H20N2O)](2) (mu-THF)(THF) (1). The molecular structure of 1 shows that it is a dimer in which the two [(eta(5)-C5H5)Yb(mu-OC20H20N2O)] units connecting via a bridging THF oxygen and two bridging oxygen atoms from Schiff base ligands. (C) 1998 Elsevier Science S.A.

YAG∶Eu~(3+)、Bi~(3+)的溶胶-凝胶法合成及其结构和发光性能

溶胶－凝胶法以其各组分混合均匀性好、反应温度低、节省能源等诸多优点而引起了人们极大兴趣［１，２］．近年来，利用该法研制玻璃和陶瓷等无机材料的报道越来越多［３，４］．但研制稀土固体发光材料的报道则较少．钇铝石榴石Ｙ３Ａｌ５Ｏ１２（ＹＡＧ）是一种很好的基…

YAG:Nd,Ho光谱性质的研究

YAG是一种多用途的激光基质材料。由于YAG的机械、热学和光学等物化综合性能良好,迄今为止它仍是最佳的掺稀土离子的固体基质材料,特别是Nd:YAG能在室温下以四能级方式、脉冲或连续工作,阈值低,效率高,是应用最广泛的激光材料之一。

Eu~(3+)在YAG中的发光性能及Eu~(3+)、Bi~(3+)间的能量传递

ＹＡＧ作为一种新型的功能材料已引起了人们极大的兴趣，我们采用溶胶、凝胶法合成了ＹＡＧ：Ｅｕ和ＹＡＧ：Ｅｕ，Ｂｉ，研究了Ｅｕ３＋在ＹＡＧ中的发光及Ｅｕ３＋，Ｂｉ３＋间的能量传递。１实验部分将纯度９９．９９％Ｙ２Ｏ３，Ｅｕ２Ｏ３和Ｂｉ２Ｏ３分别溶于ＧＲ级ＨＮＯ３中，配制成一定浓度的溶液，然后以Ｙ（ＮＯ３）３，Ｅｕ（ＮＯ３），Ｂｉ（ＮＯ３）３和Ａｌ（ＮＯ３）３为初始原料，按（Ｙ１－ｘＥｕｘ）３ＡＬ５Ｏ１２和（Ｙ１－ｘ－ｙＥｕｘＢｉｙ）３Ａｌ５Ｏ１２化学式量配比，充分混匀后加入柠檬酸，缓慢蒸干，在４００℃灼烧２ｈ