CaO-SiO2-B2O3:Sm2O3玻璃的合成及Sm3+发光性质研究

用常规的高温合成法合成了CaO-SiO2-B2O3Sm2O3玻璃, 探讨了玻璃的最佳合成温度、玻璃的吸收光谱, 并研究了其发光性质. 在CaO-SiO2-B2O3Sm2O3玻璃体系中观察到了Sm3+的发射光谱. 样品的发射光谱有3个主要荧光发射峰, 峰值波长分别为568, 605, 650 nm, 其中最强峰为605 nm,可见发射起源于Sm3+离子4f电子的f-f跃迁. 其中568 nm对应于4G5/2→6H5/2跃迁、 605 nm对应于4G5/2→6H7/2跃迁、 650 nm对应于4G5/2→6H9/2跃迁, 光谱性质表明这种玻璃体系能够把太阳光中的紫外光转换成红光, 从而增强红光的发射强度. 可以利用这些玻璃的发光性质来制备农用转光玻璃.     

SrZnO2:Eu3+, Li+长波紫外激发红光荧光体的合成及发光性能研究

采用高温固相法合成了一种长波紫外激发的SrZnO2：Eu^3＋, Li^＋发光材料, 用X射线衍射谱、荧光光谱对样品进行了表征. 结果表明, Eu^3＋离子在SrZnO2基质中主要占据Sr^2＋离子不对称性格位, 发射来源于5D0→7F2 612 nm为主的红光. 加入电荷补偿剂Li^＋离子能显著提高发光强度, 350～400 nm内的激发峰也有明显提高, 同时观察到来自Eu^3＋离子高能级5D1→7FJ（J=0～2）的跃迁发射, 并对其产生机制进行了初步探讨. 实验结果表明, SrZnO2：Eu^3＋, Li^＋是一种有发展前途的长波紫外激发红光荧光体.     

Eu3+掺杂SiO2-Al2O3-B2O3玻璃制备及光谱性能研究

高温溶制了Eu^3＋掺杂SiO2-Al2O3-B2O3-MxOy（M=Li^＋,Na^＋,K^＋,Mg^2＋,Ca^2＋,Sr^2＋,RE^3＋）硼硅酸盐玻璃,测试了玻璃样品的发射光谱、激发光谱和透射光谱,研究了不同碱金属离子、碱土金属离子对该系统荧光性能的影响。利用发射光谱计算了Ω2,Ω4以及^5D0到^7F2,^7F4的自发辐射几率和振子强度f（^5D0→^7F2）,f（^5D0→^7F4）。结果表明,材料的发射能级为^5D0→^7F1（590nm）,^5D0→^7F2（617nm）,^5D0→^7F4（698nm）,而且材料的结构对称性越差,跃迁戒律打破地越彻底,荧光发射越强。     

CaO-SiO_2-B_2O_3∶Sm_2O_3玻璃的合成及Sm~(3 )发光性质研究

用常规的高温合成法合成了CaO-SiO2-B2O3∶Sm2O3玻璃,探讨了玻璃的最佳合成温度、玻璃的吸收光谱,并研究了其发光性质。在CaO-SiO2-B2O3∶Sm2O3玻璃体系中观察到了Sm3 的发射光谱。样品的发射光谱有3个主要荧光发射峰,峰值波长分别为568,605,650nm,其中最强峰为605nm,可见发射起源于Sm3 离子4f电子的f-f跃迁。其中568nm对应于4G5/2→6H5/2跃迁、605nm对应于4G5/2→6H7/2跃迁、650nm对应于4G5/2→6H9/2跃迁,光谱性质表明这种玻璃体系能够把太阳光中的紫外光转换成红光,从而增强红光的发射强度。可以利用这些玻璃的发光性质来制备农用转光玻璃。     

Ca2Y8（SiO4）6O2：RE（RE=Eu,Tb）发光薄膜的制备及发光性能的研究

采用溶胶－凝胶法制备了稀土离子掺杂（Eu^3 ,Tb^3 )的氧磷灰石三元稀土硅酸盐Ca2Y8(SiO4)6O2发光薄膜。通过X射线衍射（XRD）,红外光谱（IR）,扫描电镜（SEM）等方法对薄膜的组成、结构、颗粒尺寸、形貌及厚度进行了研究,通过发光光谱对薄膜的发光性质进行了分析。XRD结果表明700℃时薄膜尚处于非晶态,800℃时已开始有Ca2Y8(SiO4)6O2的物相形成,1000℃时结晶已完全。这一点和红外光谱的结果相符。发光光谱测试表明Ca2Y8(SiO4)6O2:Eu^3 薄膜显示了很强的红光发射,并以Eu^3＋的^5D0-^7F2(616nm)超灵敏跃迁为最强一组。Ca2Y8(SiO4)6O2:Tb^3 的发射光谱由蓝光发射和绿光发射两部分组成,前者对应于^5D3-^7FJ,后者对应于^5D4-^7FJ(J=6,5,4,3),且以^5D4-^7F5(544nm)绿光发射为最强。     

RbLn2F7的水热合成及RbLn2F7:Eu3+(Ln=Gd,Y)的VUV光谱

利用水热方法合成出RbLn2F7（Ln=Gd，Y，Er，Yb和Lu），均为六方RbEr2F7型结构。掺杂Eu^3＋离子样品的光谱表明水热产物中氧杂质含量极低。在RbGd2F7：Eu^3＋（0．5mol％）的激发光谱中只观测到Gd^3＋离子f-f跃迁，Eu^3＋离子的激发跃迁很弱。激发Gd^3＋离子到^6IJ能级后，观测到Eu^3＋离子的特征发射，Gd^3＋离子与Eu^3＋离子之间存在能量传递过程。Eu^3＋离子的^5D0→^7F1和^5D0→F2跃迁发射较强，表明稀土离子在六方HbLn2F7中处于非中心对称的格位。     

微乳液法制备MAl2O4：Eu^2＋，Dy^3＋（M=Ca，Sr，Ba）发光材料及其发光性能

采用微乳液法合成了MAl2O4：Eu^2＋，Dy^3＋（M=Ca，Sr，Ba）长余辉发光材料，并对其晶体结构和发光性能进行了比较与讨论。XRD分析表明，所合成的Ca2O4：Eu^2＋，Dy^3＋，SrAl2O4：Eu^2＋，Dy^3＋粉体为单斜晶系结构，BaAl2O4：Eu^2＋，Dy^3＋粉体为六方晶体结构。MAl2O4：Eu^2＋，Dy^3＋（M=Ca，Sr，Ba）发光材料的激发光谱都为一宽带连续谱，表明从紫外至可见光均可有效的激发该材料。发射光谱的发射波长峰值分别为440nm（M=Ca），520nm（M=Sr）和496nm（M=Ba）。对应的发光颜色分别为蓝色、黄绿色和蓝紫色。余辉衰减曲线分为快衰减、中间过渡衰减和随后极长的慢衰减过程，符合双曲线方程I=At^-n，余辉亮度与时间顺序为Sr〉Ca〉Ba。     

Er3+和Yb3+共掺杂La2Ti2O7纳米晶的上转换发光

采用溶胶-凝胶法制备了 Er3+单掺杂A2 Ti2O7(A=La,Y,Gd)和Er3+,Yb3+共掺杂的La2 Ti2O7纳米晶样品.用X射线衍射仪、扫描电子显微镜和紫外-可见-近红外光谱仪分别对样品的结构、形貌和光吸收性质进行了表征;测试了样品在980 nm激光激发下的室温上转换光谱.结果发现,样品都发出了很强的绿光(大约在525和549 nm)和红光(大约660 nm).通过研究这些基质的晶体结构对上转换发光的影响,发现La2 Ti2O7基质中Er3+离子的上转换发射最强.对La2 Ti2O7纳米晶的上转换发光研究表明,Yb3离子能够有效地敏化Er3离子的上转换发射.对上转换发光强度与泵浦功率的依赖分析,发现红光和绿光的发射均属于双光子吸收过程,最后讨论了Er3+和Yb3的上转换发光机制.     

Er3+单掺与Er3+/Yb3+双掺杂Bi2O3-GeO2-B2O3-ZnO玻璃的光谱研究

用高温融熔法制备了Er^3＋单掺与Er^3＋/Yb^3＋双掺杂的（60-x）Bi2O3-xGeO2-30B2O3-10ZnO （x=5,10, 20, 30）系统玻璃. 用差热曲线（DTA）研究了该玻璃系统的热稳定性. 结果表明, GeO2的掺入, 使得玻璃的软化温度与结晶起始温度的差增加, 玻璃的稳定性与料性增加. 测定了玻璃的吸收光谱. 应用McCumber理论计算了Er^3＋离子的受激发射截面及Er^3＋离子^4I13/2-^4I15/2发射光谱的荧光半高宽. 从吸收光谱特性出发, 应用J-O理论计算了玻璃中Er^3＋离子的强度参数（Ω2, Ω4, Ω6）, Er^3＋离子的自发跃迁几率、荧光分支比以及辐射寿命. 在970 nm波长的激发下, 研究了样品在红外波段的荧光光谱. Yb2O3的掺入, 大幅度地提高了970 nm波长的抽运效率以及在1.54 μm波段的发光强度.     

La2CaB10O19：Eu^3＋的VUV—VIS范围光谱的研究

研究了La2CaB10O19:Eu^3 红色发光材料的高分辨发射光谱和UV－VUV激发光谱，根据发射光谱和荧光寿命，认为进入晶格的Eu^3 占据了两种格位，一种Eu^3 占据了与O^2-离子十配位的La^3 的格位，另一种Eu^3 则占据了与O^2-离子八配位的Ca^2 的格位，又从激发光谱的分析中，得到Eu^3 的电荷迁移带（CTB）是峰值位于244mm的带，而位于130－170nm之间的成份复杂的宽带包括硼酸盐基质的吸收带和Eu^3 的f-d跃迁的结论。     

Untersuchung der Phasengleichgewichte in den Systemen Sb2O3?SO3?H2O und Bi2O3?SO3?H2O

Investigation of Phase Equilibria in the Systems Sb₂O₃? SO₃? H₂O and Bi₂O₃? SO₃? H₂O Phase equilibria in the systems Sb₂O₃? SO₃? H₂O and Bi₂O₃? SO₃? H₂O within the concentration range of 1 up to 98.5% H₂SO₄ at 100°C are studied. In the system Sb₂O₃? SO₃? H₂O crystallization fields of five compounds depending on the H₂SO₄ concentration were determined: 5Sb₂O₃ · Sb₂(SO₄)₃ · 3H₂O; 7Sb₂O₃ · 2Sb₂(SO₄)₃; 2Sb₂O₃ · Sb₂(SO₄)₃; Sb₂O₃ · Sb₂(SO₄)₃ and Sb₂(SO₄)₃. The obtained compounds are identified by chemical and derivatographic analysis.     

The System Bi2O3–R2O3 (R=Y,Gd)

A new face centered cubic phase of composition Bi₃RO₆ (R?Y, Gd) is reported, and details of the Bi₂O₃–R₂O₃ (R?Y, Gd) phase diagrams are discussed. Similar compositions with R?Tb, Dy, Hc, Er are examined.     

Evaluating data for atmospheric models,an example: CH3O2 + NO2 = CH3O2NO2

Data in both directions for the title reaction have been statistically fit (weighted nonlinear least squares) to the different formalisms used by the NASA and IUPAC data evaluation panels. The data are well represented by either formalism. Master equation/RRKM methods were then employed in an attempt to reconcile the statistical formulae with theory. This was possible within reasonable bounds using the NASA formulation but more difficult using the IUPAC results. There are sufficient assumptions and unknowns in this attempt, such that the real “bottom line” is that while assuring reasonable agreement with theory is satisfying, spending much time and energy on details needed to represent pressure‐dependent rate coefficients for use in atmospheric or other models of “engineering” problems is not terribly worthwhile. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 625–632, 2005     

Isomerization of CH3O+=CHCH3 to CH2=O+CH2CH3

Ab initio calculations establish that CH₃O⁺=CHCH₃ (1) rearranges in gas phase isolation to CH₂=O⁺C₂H₅ (2) directly rather than through CH₃OCH₂CH ₂ ⁺ (3). The reaction is predicted to be antarafacial, in accord with the Woodward-Hoffmann (W-H) predictions. We predict an activation energy of 212.0 kJ/mol for this process at the QCISD(T)/6-311G**//MP2/6-311G** level. We also reinvestigated the degenerate rearrangement of CH₃O=CH ₂ ⁺ by a 1,3-sigmatropic shift. The W-H model is not a good one for the transition state (TS) for the latter reaction because the π bonding has been completely broken off. That TS is stabilized by three-center bonding between the carbons and the hydrogen being transferred. We also examined the questions of the importance of polarization functions on hydrogen and a set of outer valence functions on all the atoms in describing these hydrogen transfer TSs, and whether it is necessary to include these functions in the TS optimization runs. For the rearrangements we studied, polarization functions on hydrogen are crucial only for 1,2 hydrogen shifts. The 6-31G* basis set is adequate and good for the optimization of TSs of other ring sizes. For the 1,3 and 1,4 shifts we examined, a combination of both outer valence functions and polarization functions on hydrogen causes reductions in the computed activation energies ranging from 5.9 kJ/mol for the 1,4 shift at the RHF level to 15.6 kJ/mol for the 1,3 shift at the MP2 level.     

Kinetic flash spectroscopic study of the CH3O2?CH3O2 and CH3O2?SO2 reactions

Methylperoxy radicals were generated by the flash photolysis of azomethane–oxygen mixtures. The observed broadband spectrum of the CH₃O₂ radical is similar, but not identical to those reported previously. The CH₃O₂ decay followed second-order kinetics at high CH₃O₂ concentrations with k₄' = (2.5 ± 0.3) × 10⁸ liter/mol·sec (23 ± 2°C); 2CH₃O₂ → products (4). Because of the potential loss of CH₃O₂ through the reactions with HO₂ and CH₃O radicals subsequently formed in this system, simulations suggest that the true k₄ is in the range: 2.5 × 10⁸ ≥ k₄ ≥ 2.3 × 10⁸ liter/mol·sec. Deviations from linearity of the plot of the reciprocal of the CH₃O₂ absorbance versus time were seen at long times and were attributed to the reaction (5) with an apparent rate constant k₅' ? (1.6 ± 0.4) × 10⁵ liter/mol·sec; CH₃O₂ + Me₂N₂ → product (5). The CH₃O₂–SO₂ reaction, CH₃O₂ + SO₂ → products (16), was studied by observing CH₃O₂ decay in flashed mixtures of Me₂N₂, O₂, and SO₂. The results gave the apparent second-order rate constant k₁₆' ? (6.4 ± 1.4) × 10⁶ liter/mol·sec. It appears likely that each occurrence of reaction (5) and (16) is followed by the loss of an additional CH₃O₂ radical and that k₅ ? k₅'/2 and k₁₆ ? k₁₆'/2. Our findings suggest that a significant fraction of the SO₂ oxidation in a sunlight-irradiated NO_x?RH-polluted atmosphere, may occur by reaction with CH₃O₂ as well as from the HO and HO₂ reactions.     

固体强酸催化剂S2O2-8/ZrO2-Al2O3-M2O3(M=Cr,Ce,La)的制备

酯化反应;固体强酸催化剂S2O2-8/ZrO2-Al2O3-M2O3(M=Cr;Ce;La)的制备     

Crystal chemical aspect of synthesis of laser crystals with garnet structure in Ln2O3−Sc2O3−M2O3 systems (Ln=Y,Gd; M=Ga,Al)

Regions of existence were determined for various types of poly- and monocrystalline solid solutions (Ln₃[Sc_yM_2−y]M₃O₁₂; {Ln_3−xSc_x}[Sc_yM_2−y]M₃O₁₂; Ln₃[Ln_zSc_yM_2−y−z] M₃O₁₂; Ln=Y, Gd; M=Ga, Al) by analyzing the diagrams r^VIII−r^VI (r^VI are weighted mean dodecahedral and octahedral radii, respectively). We found the position of congruently melting compositions in r^VIII−r^VI coordinates and optimal compositions for obtaining Nd³⁺- and Cr³⁺-doped crystals. The structure of the congruently melting composition was found to be formed of “equilibrium” polyhedra, which need not be stabilized. It is shown that a congruently melting composition, which is absent in the original matrix, may be achieved by isomorphous substitutions at certain positions of the structure. The most probable mechanisms of formation of poly- and monocrystalline solid solutions with garnet structure are suggested using the calculated binodal curves of decomposition. M. V. Lomonosov Moscow Academy of Fine Chemical Technology. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 5, pp. 23–33, September–October, 1994. Translated by O. Kharlamova     

Synthesis of substitutional solid solutions in Na2O-P2O5-In2O3-M 2 III O3 (MIII = Cr, Fe, and Mn) systems

Solid solutions based on Na₇(InP₂O₇)₄PO₄ and Na₃In₂(PO₄)₃, where chromium, iron, and manganese substitute for indium, have been prepared. When chromium and iron substitute for indium in Na₇(InP₂O₇)₄PO₄, a continuous solid solution series exists. When manganese substitutes for indium, it enters the compound in the oxidation state +3. The substitution of chromium for indium in Na₃In₂(PO₄)₃ occurs within the range from 0.11 to 0.74 (mol/mol), and that of iron for indium, from 0.09 to 0.62 (mol/mol). When manganese substitutes for indium, it enters the structure of the crystalline phase in insignificant amounts as a two-charged cation.