Lu_2O_3:Dy和Lu_2O_2S:Dy荧光粉体的合成与发光特性

以NH_4HCO_3为沉淀剂,采用简易的化学共沉淀法合成了非晶态前驱沉淀物,前驱体在空气中煅烧获得了立方Lu_2O_3:Dy氧化物荧光粉,再在还原性气氛下对该氧化物进行硫化处理获得了六方Lu_2O_2S:Dy硫氧化物荧光粉。Lu_2O_3:Dy和Lu_2O_2S:Dy荧光粉分别为纳米级类球状和无规则二维板片状。光谱分析结果表明,Lu_2O_3:Dy荧光粉呈黄绿光的发射,这源自Dy~(3+)离子4f~9电子组态内~4F_(9/2)→~6H_(15/2),~6H_(13/2)的电子跃迁,其CIE颜色坐标为(0.34,0.46);Lu_2O_2S:Dy荧光粉则呈现出强烈的蓝、绿、黄及红光发射,分别来源于Dy~(3+)离子的~4F_(9/2)→~6H_(15/2),~6H_(13/2),~6H_(11/2)及~4G_(11/2)→~6H_(13/2)电子跃迁,其1931CIE颜色坐标为(0.40,0.43)。在Lu_2O_3和Lu_2O_2S晶格中Dy~(3+)离子的最佳掺杂浓度分别为0.05%和1.0%(原子分数),这两个体系的荧光猝灭均是由于Dy~(3+)→Dy~(3+)之间能量互递作用导致的。相比于Lu_2O_3:Dy氧化物荧光粉,Lu_2O_2S:Dy硫氧化物荧光粉有更高的发射及激发强度、更大的外量子效率和更短的荧光寿命。     

Er3+掺杂Li2O-SrO-ZnO-Bi2O3玻璃中Er3+离子在1.53 μm处的荧光发射特性

采用传统的熔融法制备了Er~(3+)掺杂的新型铋酸盐玻璃(Li_2O-SrO-ZnO-Bi_2O_3,LSZB),并对其光谱性质进行了表征,分析了玻璃的拉曼光谱、吸收光谱、荧光光谱,利用Judd-Ofelt理论研究了其荧光特性。LSZB玻璃样品中Er~(3+)的~4I_(13/2)→~4I_(15/2)跃迁发射峰位于1.53 μm处,半高宽约为78 nm。样品中Er~(3+)的~4I_(13/2)能级寿命为2.848 ms,量子效率为99.93%,受激发射截面达到9.76×10~(-21)cm~2。以上结果显示,Er~(3+)掺杂LSZB玻璃有良好的光谱特性。     

微波辅助水热法反应参数对NaYF4:Dy3+晶相、形貌、发光性能的影响

采用微波辅助水热法快速制备了可重复性良好的NaYF_4:Dy~(3+)样品,研究了一系列反应参数对NaYF_4:Dy~(3+)晶相、形貌、发光性能的影响。结果表明微波水热反应时间长短并未对产物的晶相、形貌、光谱性能产生明显的影响。Dy~(3+)掺杂浓度的增加并未改变样品晶相、形貌和尺寸,但发光强度发生改变,发光强度的变化趋势为先增大后减小,当Dy~(3+)掺杂浓度(物质的量分数)为1%时发光强度最强。根据具体的理论依据获得的电多极相互作用指数为6,表明Dy~(3+)之间的相互作用为电偶极-电偶极相互作用。研究了表面活性剂的种类与量对NaYF_4:Dy~(3+)晶相的影响。当使用柠檬酸钠和CTAB作为表面活性剂时,可制备得到六方相NaYF_4:Dy~(3+)。增加柠檬酸钠和CTAB的量,样品晶相未发生改变。使用EDTA-2Na作为表面活性剂时,随着EDTA-2Na量的不断增加发生从六方相到立方相晶相的转变。3种表面活性剂使用量不断增加后样品均出现尺寸减小现象。合成的一系列NaYF_4:Dy~(3+)荧光粉均在350nm紫外光激发下,出现Dy~(3+)特征峰。蓝光发射中心为479 nm,对应于Dy~(3+)的4F9/2→6H15/2跃迁;绿光发射中心为572nm,对应于Dy~(3+)的4F9/2→6H13/2跃迁,样品可实现蓝、绿发光。     

Up-conversion Properties of Er~(3+)/Yb~(3+) Co-doped Li_3Ba_2Gd_3(MoO_4)_8 Phosphors

Er~(3+)/Yb~(3+)co-doped Li_3Ba_2Gd_3(Mo O_4)_8 phosphors were synthesized by conventional solid state reaction method,and their structure and spectral properties were investigated.The diffuse reflectance spectra showed that the ~4I_(15/2)→~4I_(11/2) transition of Er~(3+)and the ~2F_(7/2)→~2F_(5/2)transition of Yb~(3+)ions were highly overlapped.Under the excitation of 980 nm,three up-conversion(UC)luminescence bands around 530,555 and 660 nm were observed,corresponding to the~2H_(11/2)→~4I_(15/2),~4S_(3/2)→~4I_(15/2) and ~4F_(9/2)→~4I_(15/2) transitions of Er~(3+)ions,respectively.The effects of the concentration and pumping power on the UC intensities of Li_3Ba_2Gd_3(Mo O_4)_8:Er~(3+)/Yb~(3+)phosphors were investigated,and the possible UC mechanism was proposed based on the results.     

基于油酸辅助水热法制备NaLuF4:Ln3+及光谱性质

采用油酸辅助水热法合成了具有上下转换发光性能的NaLuF_4∶Ce~(3+)、NaLuF_4∶Ce~(3+),Tb~(3+)、NaLuF_4∶Yb~(3+),Tm~(3+)、NaLuF_4∶Yb~(3+),Er~(3+)以及NaLuF_4∶Yb~(3+),Er~(3+),Tm~(3+)荧光粉材料。X射线衍射(XRD)表征结果表明产物各个衍射峰与标准卡片PDF#27-0726较好的吻合,得到六方相NaLuF_4晶体。扫描电镜(SEM)显示产物形貌为六棱柱,由粒径分布图可知属于微米级材料。NaLuF_4基质中单掺Ce~(3+)时,研究掺杂浓度对样品发光性能的影响表明NaLuF_4∶0.09Ce~(3+)的发光强度最大。双掺Ce~(3+)、Tb~(3+)时,详细讨论了NaLuF_4基质中Ce~(3+)→Tb~(3+)的能量传递机制,可认为是偶极-四极作用。在980 nm激光激发下,增大Yb~(3+)的掺杂浓度可以使Er~(3+)的红(~4F_(9/2)→~4I_(15/2))/绿(~2H_(11/2)→~4I_(15/2),~4S_(3/2)→~4I_(15/2))光发射比例增大,Er~(3+)的红光和绿光发射过程均属于双光子发射,Tm~(3+)的蓝光发射过程属于三光子发射,并且NaLuF_4∶0.20Yb~(3+),0.005Er~(3+),0.005Tm~(3+)样品实现了白光发射(x=0.335,y=0.385)。     

GdVO4:Ln3+(Ln=Eu,Tm,Dy)荧光粉的水热法制备及其发光性能

以EDTA为矿化剂,采用水热法制备了Gd VO4∶Dy~(3+)、Gd VO4∶Dy~(3+),Eu~(3+)和Gd VO4∶Dy~(3+),Eu~(3+),Tm~(3+)荧光粉,研究了所制备样品的相结构、形貌、荧光性质、Dy~(3+)到Eu~(3+)的能量传递及Dy~(3+)的4F9/2→6H15/2跃迁的衰减曲线。X射线衍射(XRD)确定了所合成的Gd VO4∶0.03Dy~(3+)、Gd VO4∶0.03Dy~(3+),0.07Eu~(3+)和Gd VO4∶0.03Dy~(3+),0.07Eu~(3+),0.07Tm~(3+)样品均为四方晶系;扫描电镜(SEM)显示Gd VO4∶0.03Dy~(3+),0.07Eu~(3+)和Gd VO4∶0.03Dy~(3+),0.07Eu~(3+),0.07Tm~(3+)均为棒状结构,平均长度分别约为0.458和0.491μm;通过研究Gd VO4∶Dy~(3+),Eu~(3+)的发射光谱和衰减曲线,佐证了Dy~(3+)到Eu~(3+)的能量传递过程,并确定了其能量传递的机制为偶极-偶极相互作用。通过调节Gd VO4∶0.03Dy~(3+),x Eu~(3+)荧光粉中Eu~(3+)的掺杂浓度实现了准白光输出(0.424,0.350);调节Gd VO4∶0.03Dy~(3+),0.07Eu~(3+),y Tm~(3+)荧光粉中Tm~(3+)的掺杂浓度,也实现了白光输出(0.346,0.301)。     

Er3+,Yb3+共掺杂NaY(WO4)2上转换荧光粉的制备及其发光性能

应用传统水热法合成出具有四方白钨矿结构的NaY(WO_4)_2微米颗粒及一系列Er~(3+)/Yb~(3+)共掺杂NaY(WO_4)_2上转换荧光粉。利用XRD、SEM、TEM、HRTEM、粒度分布和上转换发光光谱对样品的物相、形貌及上转换发光性能进行分析表征。结果表明,p H值对于制备具有同一形貌的纯相NaY(WO_4)_2微米颗粒发挥重要作用。随着pH值的升高,可以完成从八面体到拟立方体再到片状颗粒的形貌转变。在980 nm近红外光激发下,观测到525及553 nm处的强绿光发射,对应Er~(3+)的~2H_(11/2)→~4I_(15/2)与~4S_(3/2)→~4I_(15/2)跃迁,以及650~680 nm范围内的弱红光发射,对应Er~(3+)的~4F_(9/2)→~4I_(15/2)跃迁,且绿、红光上转换发射均属于双光子过程。此外,通过调节NaY(WO_4)_2∶Er~(3+),Yb~(3+)荧光粉中Yb~(3+)的浓度,可实现对绿光色度的有效控制。     

La_(2.4)Mo_(1.6)O_8∶Yb~(3+),Er~(3+)材料的制备及其上转换发光性质

采用高温固相法制备了La_(2.4)Mo_(1.6)O_8∶Yb~(3+),Er~(3+)荧光粉。通过X射线衍射(XRD)和上转换发射光谱对样品进行了相结构和发光性质表征。XRD实验结果表明:合成的样品为面心立方萤石结构(Fm-3m)的La_(2.4)Mo_(1.6)O_8相。在980 nm红外光激发下,La_(2.4)Mo_(1.6)O_8∶Yb~(3+),Er~(3+)荧光粉发出分别来自Er~(3+)离子的~2H1_(1/2)→~4I_(15/2)、~4S_(3/2)→~4I_(15/2)跃迁的绿光(主峰为548和529 nm)和~4F_(9/2)→~4I_(15/2)跃迁的红光(主峰为670 nm)。进一步地,对样品中可能的上转换发光机制进行了讨论。     

Ce~(3+),Mn~(2+)共掺NaYF_4微米六棱柱的发光性能和能量传递研究

通过水热法合成了单分散的六方相NaYF_4:5%Ce~(3+),x%Mn~(2+)(摩尔分数,x=0,5,10,15)微米六棱柱。扫描电镜(SEM)分析表明,样品尺寸均匀,平均长度和平均高度约为2.02μm和700 nm。NaYF_4:5%Ce~(3+),x%Mn~(2+)发光性质的研究结果表明,在激发谱中,245 nm的激发峰来自于Ce~(3+)的4f→5d跃迁;332 nm的激发峰对应于Mn~(2+)的6A1(6S)→4E(4D)跃迁和自陷激子(STE)的激发。在发射谱中,302和422 nm的宽带发射峰分别对应Ce~(3+)的5d→4f跃迁和基质中自陷激子的发光;538和587 nm的宽带发射峰分别对应Mn~(2+)的~4A_1(~4G)→6A1(6S)跃迁和4T1(4G)→6A1(6S)跃迁。随着Mn~(2+)含量的增加,Ce~(3+)的发射强度逐渐减弱,而Mn~(2+)的538 nm(~4A_1(~4G)→6A1(6S))发射峰强度逐渐增强,这表明在NaYF_4基质中,存在Ce~(3+)和Mn~(2+)之间的能量传递。     

Er~(3+)和Ce~(3+)/Ce~(4+)掺杂β-BaB_2O_4纳米棒的制备、结构与发光性质

以Ba(NO_3)_2、NaBH_4、Er_2O_3和CeO_2为原料,在十六烷基三甲基溴化铵(CTAB)表面活性剂辅助下,采用水热法制备了β-BaB_2O_4(β-BBO)纳米棒,稀土离子Er~(3+)单掺杂的β-BBO(β-BBO:Er~(3+))及Er~(3+)和Ce~(3+)/Ce~(4+)共掺杂的β-BBO(β-BBO:Er(3+)/Ce~(3+)/Ce~(4+))纳米棒.通过X射线粉末衍射(XRD)、傅里叶变换红外(FTIR)光谱、拉曼光谱、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和光致发光(PL)光谱分别对样品的物相、结构、形貌、成分及光致发光性质进行了表征.研究结果表明:微量稀土离子掺杂并不改变β-BBO的结构,制得的纳米棒尺寸均匀,长度在200-500 nm之间,直径在10-20 nm之间;β-BBO:Er~(3+)和β-BBO:Er~(3+)/Ce~(3+)Ce~(4+)纳米棒在400nm光激发下,在可见光范围内都观察到中心波长为515和542 nm的绿光.对发光机理的初步研究表明:发光分别对应于Er~(3+)的~2H_(11/2)→~4I_(15/2),~4S_(3/2)→~4I_(15/2)跃迁,铈离子以Ce~(3+)和Ce~(4+)两种形式存在于体系中,Ce~(3+)对Er~(3+)起敏化作用,可以显著增强β-BBO:Er~(3+)/Ce~(3+)/Ce~(4+)纳米棒的发光强度,存在Ce~(3+)→Er~(3+)的能量传递过程.     

Spin-Hamiltonian parameters and defect structure for the rhombic Dy3+ center in AgCl crystal

Based on the defect model that the rhombic Dy(3+) center in AgCl crystal is formed by substitutional Dy3+ ion associated with two nearest Ag+ vacancies (VAg) along the <110> and <110> axes owing to charge compensation, the spin-Hamiltonian parameters (g factors gi and hyperfine structure constants 161Ai and 163Ai, where i=x, y, z) of this rhombic Dy3+ center are calculated from a diagonalization (of energy matrix) method. In the method, the Zeeman (or magnetic) and hyperfine interaction terms are attached to the classical Hamiltonian used in the calculation of crystal-field energy levels and a 66×66 energy matrix concerning this Hamiltonian is constructed by taking all the ground-term multiplets 6HJ (J=15/2, 13/2, 11/2, 9/2, 7/2, 5/2) into account. The calculated results (g factors gi and average |A(161Dy3+)| and |A(163Dy3+)|) are in reasonable agreement with the experimental values. From the calculations, the above defect model of rhombic Dy3+ center is confirmed, the defect structure of this Dy3+ center (characterized by the displacement of Cl- ligand caused by VAg) is obtained and the components of hyperfine structure constants Ai(161Dy3+) and Ai(163Dy3+) are predicted. The results are discussed.     

电子俘获材料Zn4B6O13:Dy3+的热释光特性研究

通过高温固相扩散反应合成了稀土元素镝掺杂的Zn4-xB6O13:xDy3+磷光体.测定了该化合物在高能60Co伽玛射线辐照下的热释发光曲线和三维热释光谱.三维热释光谱表明,位于大约480nm和580nm的发光谱带来自于Dy3+离子的f-f跃迁.基质中掺杂的Dy3+离子浓度的变化能够改变陷阱的相对分布,随着Dy3+浓度的增加,发光峰温向高温方向移动,这可提高剂量器的热稳定性.当辐照剂量增加时,发光峰温亦向高温方向移动,即陷阱加深.确定了Zn3.86B6O13:0.16Dy3+样品主峰的陷阱深度E=0.73eV,频率因子S=2.43×109s-1.在1～100Gy治疗级范围内,Zn3.86B6O13:0.16Dy3+对60Co伽玛射线辐照的热释光剂量响应呈良好的线性关系.实验结果表明,Zn3.86B6O13:0.16Dy3+是一个潜在的应用于临床医疗的伽玛射线电离辐射热释光剂量计材料.     

Synthesis and characterization of a family of structurally characterized dysprosium alkoxides for improved fatigue-resistance characteristics of PDyZT thin films

Using either an ammoniacal route, the reaction between DyCl3, Na0, and HOR in liquid ammonia, or preferentially reacting Dy(N(SiMe3)2)3 with HOR in a solvent, we isolated a family of dysprosium alkoxides as [Dy(mu-ONep)2(ONep)]4 (1), (ONep)2Dy[(mu3-ONep)(mu-ONep)Dy(ONep)(THF)]2(mu-ONep) (2), (ONep)2Dy[(mu3-ONep)(mu-ONep)Dy(ONep)(py)]2(mu-ONep) (3), [Dy3(mu3-OBut)2(mu-OBut3(OBut)4(HOBut)2] (4), [Dy3(mu3-OBut)2(mu-OBut)3(OBut)4(THF)2] (5), [Dy3(mu3-OBut)2(mu-OBut)3(OBut)4(py)2] (6), (DMP)Dy(mu-DMP)4[Dy(DMP)2(NH3)]2 (7), [Dy(eta6-DMP)(DMP)2]2 (8), Dy(DMP)3(THF)3 (9), Dy(DMP)3(py)3 (10), Dy(DIP)3(NH3)2 (11), [Dy(eta6-DIP)(DIP)2]2 (12), Dy(DIP)3(THF)2 (13), Dy(DIP)3(py)3 (14), Dy(DBP)3(NH3) (15), Dy(DBP)3 (16), Dy(DBP)3(THF) (17), Dy(DBP)3(py)2 (18), [Dy(mu-TPS)(TPS2]2 (19), Dy(TPS)3(THF)3 (20), and Dy(TPS)3(py)3 (21), where ONep = OCH2CMe3, OBut) = OCMe3, DMP = OC6H3(Me)(2)-2,6, DIP = OC6H3(CHMe2)(2)-2,6, DBP = OC6H3(CMe3)(2)-2,6, TPS = OSi(C6H5)3, tol = toluene, THF = tetrahydrofuran, and py = pyridine. We were not able to obtain X-ray quality crystals of compounds 2, 8, and 9. The structures observed and data collected for the Dy compounds are consistent with those reported for its other congeners. A number of these precursors were used as Dy dopants in Pb(Zr0.3Ti0.7)O3 (PZT 30/70) thin films, with compound 12 yielding the highest-quality films. The resulting Pb0.94Dy0.04(Zr0.3Ti0.7)O3 [PDyZT (4/30/70)] had similar properties to PZT (30/70), but showed substantial resistance to polarization reversal fatigue.     

Luminescence Properties of Dy3+ Doped EuAl3(BO3)4 Crystals

EuAl3(BO3)4 and Dy3+:EuAl3(BO3)4 crystals were synthesized and their luminescence properties were studied. The EuAl3(BO3)4 crystals have strong red emission. In the Dy3+ doped EuAl3(BO3)4 crystals, the Dy3+ strongly sensitized the luminescence of the Eu3+. A resonance mechanism of the energy transfer was suggested. The optimum Dy3+ concentration of the sensitization effect was 0.2. When the Dy3+ concentration was higher than 0.2, the quick drop of the Eu3+ 613 nm emission for DyxEu1-xAl3(BO3)4 was attributed to the Dy3+ concentration quenching effect.     

Studies on mixed ligand complexes of samarium(III), europium(III) and dysprosium(III) with 1-nitroso-2-naphthol and trioctylphosphine oxide

The extraction behavior of Sm(III), Eu(III) and Dy(III) with 1-nitroso-2-naphthol (HA) and trioctylphosphine oxide (TOPO) in methyl isobutyl ketone (MIBK) from aqueous NaClO₄ solutions in the pH range 4–9 at 0.1M ionic strength has been studied. The equilibrium concentrations of Sm and Dy were measured using their short-lived neutron activation products,¹⁵⁵Sm and^165mDy, respectively. In the case of Eu, the concentrations were assayed through the^152,154Eu radiotracer. The distribution ratios of these elements were determined as a function of pH, 1-nitroso-2-naphthol and TOPO concentrations. The extractions of Sm, Eu and Dy were found to be quantitative with MIBK solutions in the pH range 5.9–7.5, 5.6–7.5 and 5.8–7.5, respectively. Quantitative extraction of Eu was also obtained between pH 5.8 and 8.8 with chloroform solutions. The results show that these lanthanides (Ln) are extracted as LnA₃ chelates with 1-nitroso-2-naphthol alone, and in the presence of TOPO as LnA₃(TOPO) and LnA₃(TOPO)₂ adducts. The extraction constants and the adduct formation constants of these complexes have been calculated.     

Chemical Bond Parameters in Sr_3MRhO_6(M=Rare earth)

over tile years, tile collcept of bolld covalellcy or ionicity has been proved to be a veryilllpol'tallt quantity in classifyillg and explaining many basic properties of molecules andsolids from the viewpoint of the electronic structure. Nevertheless, previous study in thisaspect was only on binary crystals, which limited the usefulness of the theory. Therecently proposed method I for the evaluation of chemical bond parameters includingbond covalency has made the study on crystals with multipl…     

A simple method to synthesize Dy(OH)(3) and Dy(2)O(3) nanotubes

Here we report the first synthesis of Dy(OH)(3) nanotubes by facile hydrothermal treatment of bulky Dy(2)O(3) crystals. Dy(OH)(3) nanotubes were calcined to produce Dy(2)O(3) nanotubes. Ho(OH)(3) and Ho(2)O(3) nanotubes were also obtained by the same method. The growth of nanotubes occurred through a dissolution-recrystallization process.     

Electroreduction of Dy(III) assisted by Zn and its co-deposition with Zn(II) in LiCl–KCl molten salt

To recover dysprosium (Dy) from LiCl–KCl molten salt, the electrochemical mechanism of Dy(III) on liquid Zn electrode and co-deposition of Dy(III) and Zn(II) on W electrode were studied using electrochemical methods. Cyclic voltammetry results demonstrated that the redox process of Dy on liquid Zn electrode is reversible and controlled by diffusion. Reverse chronopotentiograms showed that the transition time ratio of reduction and oxidation is ~3:1, revealing the redox of Dy on liquid Zn electrode is a kind of soluble–soluble system: Dy(III) + 3e⁻ = (Dy–Zn)_solution. The half-wave potential of Dy(III) was almost constant with the increase in scanning rate. The electrochemical separation of metallic Dy from the molten salt was performed using constant potential electrolysis, and the product characterized using X-ray diffraction and scanning electron microscopy–energy-dispersive X-ray spectroscopy was the thermodynamic unstable compound DyZn₅. Also, the co-deposition mechanism of Dy(III) and Zn(II) was explored, indicating that Dy(III) could deposit on pre-deposited Zn and form Dy–Zn compounds: Zn(II) + 2e⁻ = Zn and xDy(III) + yZn + 3xe⁻ = Dy_xZn_y. Moreover, the effect of Dy(III) concentration on the formation of Dy–Zn compounds was investigated. The redox peak currents corresponding to different Dy–Zn compounds changed with the increase in Dy(III) concentration. The co-deposition of Dy(III) and Zn(II) was performed using constant current electrolysis at diverse Dy(III) concentrations. The different Dy–Zn compounds were produced by controlling Dy(III) concentration.     

Effects of 3d-4f magnetic exchange interactions on the dynamics of the magnetization of Dy(III)-M(II)-Dy(III) trinuclear clusters

[{Dy(hfac)(3)}(2){Fe(bpca)(2)}] x CHCl(3) ([Dy(2)Fe]) and [{Dy(hfac)(3)}(2){Ni(bpca)(2)}]CHCl(3) ([Dy(2)Ni]) (in which hfac(-)=1,1,1,5,5,5-hexafluoroacetylacetonate and bpca(-)=bis(2-pyridylcarbonyl)amine anion) were synthesized and characterized. Single-crystal X-ray diffraction shows that [Dy(2)Fe] and [Dy(2)Ni] are linear trinuclear complexes. Static magnetic susceptibility measurements reveal a weak ferromagnetic exchange interaction between Ni(II) and Dy(III) ions in [Dy(2)Ni], whereas the use of the diamagnetic Fe(II) ion leads to the absence of magnetic exchange interaction in [Dy(2)Fe]. Dynamic susceptibility measurements show a thermally activated behavior with the energy barrier of 9.7 and 4.9 K for the [Dy(2)Fe] and [Dy(2)Ni] complexes, respectively. A surprising negative effect of the ferromagnetic exchange interaction has been found and has been attributed to the structural conformation of these trinuclear complexes.     

La0.5R0.5Ba2Cu3O7,Pr0.5R0.5Ba2Cu3O7以及RBa2Cu3o7（R=稀土）的键共价性计

使用复杂晶体化学键理论计算了Ｌａ０．５Ｒ０．５Ｂａ２Ｃｕ３Ｏ７（Ｒ＝Ｐｒ,Ｎｄ,Ｓｍ,Ｅｕ,Ｇｄ,Ｄｙ,Ｙ,Ｈｏ,Ｅｒ,Ｔｍ,Ｙｂ,Ｌｕ）（Ｌａ－Ｒ１２３）,Ｐｒ０．５Ｒ０．５Ｂａ２Ｃｕ３Ｏ７（Ｒ＝Ｌａ,Ｎｄ,Ｓｍ,Ｅｕ,Ｇｄ,Ｄｙ,Ｈｏ,Ｙ,Ｅｒ,Ｔｍ,Ｙｂ,Ｌｕ）（Ｐｒ－Ｒ１２３）以及ＲＢａ２Ｃｕ３Ｏ７（Ｒ＝Ｌａ,Ｐｒ,Ｎｄ,Ｓｍ,Ｅｕ,Ｇｄ,Ｄｙ,Ｈｏ,Ｙ,Ｅｒ,Ｔｍ）（Ｒ１２３）中Ｃｕ－Ｏ键的键共价性,结果表明Ｐｒ－Ｒ１２３,Ｌａ－Ｒ１２３,以及Ｒ１２３都应具有超导性,而实验结果是Ｌａ０．５Ｐｒ０．５Ｂａ２Ｃｕ０７,Ｒ０．５,Ｐｒ０．５Ｂａ２Ｃｕ３Ｏ７（Ｒ＝Ｌａ,Ｎｄ,Ｓｍ,Ｅｕ,Ｇｄ）无超导性,产生这种矛盾的原因尚不明确,需要做进一步的研究。