纳米Y_2O_3∶Eu~(3+)中S_6格位电荷迁移带的光学特性

在Y2 O3 ∶Eu3 + 体材料和纳米材料中 ,观察到紫外激发下处于S6格位的Eu3 + 的5D0 →7F1发射 ( 5 82nm)的强度 ,相对处于C2 格位的5D0 →7F0 发射 ( 5 80nm)的强度 ,随着激发波长在 2 0 0～ 3 0 0nm紫外区由长变短而增强。这一现象说明Y2 O3 ∶Eu3 + 中两种格位的电荷迁移带及基质激发的性质不同。光谱分解得出S6格位的电荷迁移带位于C2 格位电荷迁移带的高能侧 ,Y2 O3 基质倾向于向S6格位进行能量传递。与体材料相比 ,两种格位的电荷迁移带在纳米材料中都发生红移 ;相对于C2 格位的电荷迁移带 ,S6格位的电荷迁移带强度在纳米材料中比在体材料中明显降低 ,并对结果进行了讨论。     

Ln7O6（BO3）（PO4）2：Eu（Ln=Al,Gd,Y）的UVU—UV激发和辐射发光

本文报道了Ln7O6(BO3)(PO4)2:Eu(Ln=La,Gd,Y)在UVU－UV区的激发光谱及Eu^3 在可见区的发射光谱,其激发光谱包括基质在真空紫外区的激发带和激活剂离子在紫外区的Eu^3 -O^2-电荷迁移带,随着La^3 ,Gd^3 ,Y^3 离子半径逐渐减小,Eu^3 -O^2-电荷迁移带的重心位置逐渐向高能量方向移动,Gd7O6(BO3)(PO4)2:Eu和Y7O6（BO3）（PO4）2：Eu在真空紫外区的吸收与Eu^3 -O^2-电荷迁移带位于紫外区的吸收的比值要高于在La7O6(BO3)(PO4)2:Eu中的这个比值,激发能可被基质吸收,传递给激活剂离子,得到Eu^3 的红光发射,在Gd7O6(BO3)(PO4)2:Eu中,^5D0→^7F1的发射强度较强,在Y7O6（BO3）（PO4）2：Eu中,^5D0→^7F2和^5D0→^7F3的跃迁较强。     

纳米Gd2O3中两种格位Eu3+的电荷迁移态激发跃迁

观测了粒径分别为15,23,135m的立方相Gd2O3：Eu^3 的选择激发光谱、发射光谱和激发光谱。受强量子限域效应的影响,纳米Gd2O3：Eu^3 的激发光谱的强度表现出对颗粒尺寸的明显依赖性。用Jorgensen公式计算电荷迁移带的位置,与实验测得激发光谱中位置相一致。通过电荷迁移带不同位置的选择激发光谱可以分辨出立方相Gd2O3：Eu^3 中C2和S6格位Eu^3 的发光,从选择激发的发射光谱和激发光谱结果计算出C2和S6格位电荷迁移带的激发光谱,与实验结果相符合。     

Eu^3 和Tb^3 在LnBaB9O16中的紫外和真空紫外发光性质

研究了Tb^3 和Eu^3 在LnBaB9O16(Ln=La,Gd,Y,Lu)中的紫外和真空紫外光谱性质。X射线粉末衍射数据指标化结果表明,LnBaB9O16(Ln=La,Gd,Y,Lu)系列化合物属于三方晶系.Eu^3 的荧光光谱结果表明,LaBaB9O16和GdBaB9O16中稀土离子占据非中心对称的格位,Eu^3 在其中的特征发射以^5D0→^7F2电偶极跃迁为主;而在YBaB9O16和GdBaB9O16中稀土离子占据中心对铱性的格位,E^3 在其中的特征发射以^5D0→^7F1磁偶极跃迁为主．Tb^3 在LaBaB9O16和GdBaB9O16中的发射为^5D3→^7F0和^5D4→FJ(J=0-6)辐射跃迁,在YBaB9O16和LuBaB9O16中只能观察到^D4→^7FJ(J=3-6)辐射跃迁。与Eu^3 的发光性质相反,Tb^3 占据非中心对称的格位时的发射强度比占据中心对称的格位时要弱得多．Eu^3 和Tb^3 掺杂的样品在真空紫外波段的吸收弱。     

红色荧光粉Ca4(La1-x-yGdxYy)1-nO(BO3)3:nEu3+的发光和优化

用高温固相法合成了红色荧光粉Ca4（La1-x-yGdxYy）1-nO（BO3）3：nEu^3＋（LnCOB：Eu,Ln=La1-x-y-GdxYy）,并对其在真空紫外至可见范围的发光性质进行了系统的研究,找出发光较好的组分范围并与某些商品红色荧光粉进行了比较。LnCOB：Eu在254nm紫外线激发下的发射光谱为Eu^3＋的^5D0→^7FJ（J=0,1,2,3,4）的特征跃迁。监测其最强的^5D0→^7F2发射线,其激发光谱在250nm左右有一个宽的激发带,归属于Eu-O电荷迁移带,适于用254nm汞线激发;在300—450nm有一些弱的归属于Eu^3＋的f-f跃迁的锐吸收峰;在真空紫外区184—188nm附近有一个宽带,为基质吸收带,并可能包含了Eu^3＋的f-d跃迁。在Ca4GdO0（BO3）3：Eu^3＋的激发光谱中,还包含了Gd^3＋的^8S7/2→^6GJ跃迁,此跃迁增强了荧光粉在184～188nm附近的激发强度。     

Eu3+和Tb3+掺杂的Y2SiO5体系发光特性研究

采用溶胶－凝胶法合成了Eu^3 和Tb^3掺杂的Y2SiO5基发光材料，通过测量它们的激发光谱和发射光谱，研究了它们的发光特性，探讨了材料中Tb^3和Eu^3 两种发光中心间的能量关系。结果表明，Eu^3＋在其中的特征发射以^5D0→^7F2电偶极跃迁为，Eu^3处于非反演对称中心格位；Tb^3在其中的发射为^5D4→^7FJ(J＝4－6）跃迁发射。当Eu^3和Tb^3共存于Y2SiO5基质中时Eu^3的发射增强，Tb^3的发射减弱，存在Tb^3→Eu^3能量传递，Tb^3对Eu^3具有敏化作用。     

Ln7O6(BO3)(PO4)2:Eu(Ln=La,Gd,Y)的VUV-UV激发和辐射发光

本文报道了Ln 7O6(BO3)(PO4)2:Eu(Ln=La,Gd,Y)在VUV-UV区的激发光谱及Eu3+在可见区的发射光谱.其激发光谱包括基质在真空紫外区的激发带和激活剂离子在紫外区的Eu3+-O2-电荷迁移带,随La3+,Gd3+,Y3+离子半径逐渐减小,Eu3+-O2-电荷迁移带的重心位置逐渐向高能量方向移动,Gd7O6(BO3)(PO4)2:Eu和Y7O6(BO3)(PO4)2:Eu在真空紫外区的吸收与Eu3+-O2-电荷迁移带位于紫外区的吸收的比值要高于在La7O6(BO3)(PO4)2:Eu中的这个比值.激发能可被基质吸收,传递给激活剂离子,得到Eu3+的红光发射.在Gd7O6(BO3)(PO4)2:Eu中,5D0→7F1的发射强度较强,在Y7O6(BO3)(PO4)2:Eu中,5D0→7F2和5D0→7F3的跃迁较强.     

GdVO4：Eu^3＋的激发光谱特性研究

测量了GdVO4：Eu^3 在室温下的光致发光光谱;研究了不同掺杂方式和烧结气氛对多晶GdVO4：Eu^3 发光性质的影响,探讨了GdVO4：Eu^3 的激发光谱在200～350nm范围内激发带的来源和GdVO4：Eu^3 中的能量传递。在200～350nm范围内的激发带可解释为来自于钒酸根团的配体O到V的电荷迁移跃迁吸收;硝酸溶液使部分正GdVO4形成多钒酸盐,还原气氛使GdVO4产生O空位和部分V变价,影响了钒酸根团间的电荷迁移跃迁吸收和钒酸根团间、钒酸根团与Eu^3 间的能量传递。产生激发谱带蓝移和激发带间强度比例变化。GdVO4中VO4^3-的π轨道能使得VO4^3-和稀土离子(Gd^3 、Eu^3 )的电子波函数有效地重叠,从而VO4^3-和稀土离子可通过交换作用有效地传递能量。GdVO4：Eu^3 在200nm处的吸收很弱,在此位置也没有Gd^3 或Eu^3 的4f^n-1 5d的吸收和明显的4f^n高能级吸收,而激发却十分有效,可解释为由于存在VC4^3-与Gd^3 或Eu^3 的4f^n高能级间有效的能量传递所致;由于Gd^3 的特征发射恰好在基质的强激发带。且Gd^3 的特征发射没有出现,可存在Gd^3 →VO4^3-→Eu^3 的能量传递。Gd^3 和^6GJ、^6PJ能级间隔与Eu^3 的^7Fl、^5D0能级间隔相近,处于^6GJ态的Gd^3 可通过共振能量传递激发：Eu^3 到^5Dn态,这可导致Gd^3 →Eu^3 离子的能量传递。     

温度和浓度对分散在SiO2中Y2O3:Eu3+纳米材料发光的影响

讨论了分散在SiO2中的Y2O3：Eu纳米发光材料在不同浓度和不同灼烧温度下光谱的变化规律,在室温紫外激光波长激发下不同灼烧温度下样品的发射光谱。从光谱上看到在一定浓度下随着灼烧温度的升高发光变强,而且在一定温度下随浓度提高发光变强。尤其在^5D0→^7F0跃迁谱线的强度明显高于^5D0→^7F2的电偶极跃迁强度,并分析了原因。探讨了合理的掺杂浓度和灼烧温度,并测量了Y2O5：Eu质量分数为5％时,灼烧温度在1300℃时的激发光谱和格位选择激发光谱。样品平均粒径50nm,得到在不同波长激发下的^5D0→^7F0和^5D0→^7F2选择激发光谱。分析认为Eu^3 存在着4种格位,并对其进行了初步的分析讨论。     

Y2O2S:Eu3+,Mg2+,Ti4+红色材料的制备和长余辉性能

用高温固相法制备了Y2O2S：Eu^3 ,Mg^2 ,Ti^4 红色长余辉材料,余辉时间达到1h以上,X射线衍射测量表明材料的晶体结构为Y2O2S。发射光谱对应了Eu^3 离子^5DJ(J=0,1,2,3)→^7FJ(J=0,1,2,3,4))的特征发射;激发光谱主峰位于345nm,另外在260,396,468,540nm等处也存在激发峰。对比测量了Y2O2S：Eu^3 ,Mg^2 ,Ti^4 和Y2O2S:Eu^3 的热释发光曲线,Y2O2S:Eu^3 的热释发光曲线可以拟合成3个热释发光峰的叠加：237,226,301K;而Y2O2S：Eu^3 ,Mg^2 ,Ti^4 的热释发光曲线可以拟合成5个热释发光峰的叠加：149,215,262,287,334K,并计算了相应的陷阱能级。Ti^4 是引起较深陷阱能级的主要原因,Mg^2 起电荷补偿的作用。     

Fine structure and isotope shift of the 3s4d 3 D-3s3p 3 P, 3s5d 3 D-3s3p 3 P and 3p 2 3 P-3s3p 3 P Transitions of MgI

Summary We report the measurements of the³ D(3s4d)-³ P(3s3p)³ D(3s5d)-³ P(3s3p), and³ P(3p ²)-³ P(3s3p) transition frequency of MgI, the fine-structure separation and isotope shift between²⁴Mg and²⁶Mg. The measurements have been performed in a metastable atomic beam; a good agreement is found for data already existing in the literature. The accuracy of the measurements reported in this paper is mainly limited by the Doppler broadening of theI ₂ transitions used as a reference and by the precision in the knowledge of the related wavelengths.     

The gas phase infrared band contours of s-triazine and s-triazine-d3: The fundamentals of C3N3H3 and C3N3D3 and some overtone and combination bands of C3N3H3

The systematic application of band contour techniques to account for most of the observed features of the ir spectra of s-triazine and s-triazine-d₃ have been made as well as a critique as to the limitations of such methods. The experimental and computer methods used to study the gas phase infrared band contours of s-triazine and s-triazine-d₃ are out-lined. Contours of the five E′ fundamentals of s-triazine have been recorded under moderate resolution and analyzed to give the Coriolis constants $\text{ζ}{}_{\mathrm{i}}{}^{\mathrm{z}}$, i = 6–10. The effects of l-resonance are very apparent for ν₈ and ν₉, in the form of holes in the Q branches of these bands. Under the highest resolution available, ν₆ and ν₁₀ also show l-resonance effects. Values of the l-doubling constants $\text{q}{}_{\mathrm{i}}{}^{\mathrm{(+)}}$ were obtained for these four fundamentals. One of the parallel A₂″ fundamentals of C₃H₃N₃ (ν₁₂) has also been studied. It lies close to ν₁₀(E′) and an A × E type of second-order Coriolis resonance may be the cause of the intensity enhancement observed in the inner wings of the ν₁₂ and ν₁₀ bands. Hot bands of the type (ν_i + nν₁₄ ? nν₁₄) have been observed in the contours of ν₈, ν₁₀, and ν₁₂. This is felt to be responsible for the large difference between our observed zeta sum (?1.30) and the theoretical sum (?1.00).The gas phase infrared band contours of the five E′ and 2A₂″ fundamentals of C₃N₃D₃ have also been recorded under moderate resolution. From P-R separations and by computer simulation of the contours, values of the Coriolis constants $\text{ζ}{}_{\mathrm{i}}{}^{\mathrm{z}}$ have been obtained for the E′ modes. The effects of l-resonance have been observed for ν₈(E′) and ν₁₀(E′) and values of the l-doubling constants $\text{q}{}_{\mathrm{i}}{}^{\mathrm{(+)}}$ have been estimated. An extensive series of hot bands of the type (ν₁₂ + nν₁₄ ? nν₁₄) has been observed in the contour of the ν₁₂ (A₂″) fundamental. The mass effect on the Coriolis constants has been discussed.Infrared band contours of the overtone 2ν₇ and seven degenerate E′ combination bands of C₃N₃H₃ have been recorded under moderate resolution. Analysis of these contours using the P-R separation method and computer simulation of the contours has given values of $\text{ζ}{}_{\mathrm{<mtext>eff</mtext>}}{}^{\mathrm{z}}$ for these bands. Fermi resonance between 2ν₇ and ν₆ has been analyzed. The importance of considering both the observed contour as well as the observed frequency when assigning higher tone bands is illustrated.     

LaGaO3:RE3+(RE3+=Eu3+,Ho3+)的光谱

本文用固态反应合成了钙钛矿型的LaGaO3和LaGaO3:RE3+(RE3+=Eu3+,Ho3+)荧光体,并观察了物相随不同的激活离子浓度的变化。测量了化合物在室温下的反射光谱,激发光谱和荧光光谱。研究了Eu3+的D0→7F2和Ho3+的5S2→5I8的荧光强度与激活离子浓度的关系,发现了浓度猝灭,并得到了最大荧光强度的浓度值。     

Dielectric investigations of solid solutions SrTiO3-KTaO3 and SrTiO3-KNbO3

The temperature dependences of the dielectric constant and dielectric hysteresis loops in ceramic samples of (1 ? x)SrTiO_3?x KNbO₃ and (1 ? x)SrTiO_3?x KTaO₃ (0 ≤ x ≤ 0.3) solid solutions prepared using different heat treatments have been investigated. Phase diagrams of the studied solid solutions have been constructed in the T-x coordinates. It has been shown that, after quenching of samples (spontaneous cooling at room temperature after long-term heating at the sintering temperature of the ceramic samples), the temperature of the induced phase transition increases because of the weakening of random electric fields associated with nonisovalent impurities due to their “frozen” nonequilibrium redistribution. For small concentrations x, strong dielectric relaxation is observed in the temperature range of 150–250 K. A model of relaxing centers, which is based on the local charge compensation of heterovalent impurities, has been proposed.     

Infrared spectra of matrix isolated BH3NH3, BD3ND3, and BH3ND3

The infrared spectra of ammonia-borane, BH₃NH₃, and two of its deuterated isotropic species, BD₃ND₃ and BH₃ND₃, isolated in argon matrix at liquid hydrogen temperature have been measured. Well resolved bands for these three isotopic species have been observed for all the fundamentals. A complete frequency assignment based on C₃v molecular symmetry has been made. A set of force constants have been calculated from the data for the two isotopes BH₃NH₃ and BD₃ND₃ using a valence force field. The agreement between experiment and frequencies calculated from these force constants for the mixed isotopic species, BH₃ND₃, substantiates the present assignment.     

Terahertz Vibrational Modes in CH3NH3PbI3 and CsPbI3 Perovskite Films

JETP Letters - Films of CH3NH3PbI3 organometallic perovskite, which is currently considered as a promising basic material for new-generation solar cells, as well as films containing CsPbI3...     

Ba3La(BO3)3基质中Tb3+的光致发光

以高温固相法合成了Ba3La(BO3)3∶Tb3 发光材料。在254nm紫外光激发下,研究了Ba3La(BO3)3∶Tb3 的激发光谱、发射光谱、发光强度与Tb3 浓度的关系。确定了Ba3La(BO3)3基质中Tb3 的自身浓度猝灭机理;探讨了助熔剂LiCO、敏化剂Ce3 、Bi3 的加入对荧光粉的发光强度的影响。     

Modulated magnetic structures of ErPb3, HoPb3, ErTl3 and HoTl3

Neutron diffraction experiments have been carried out on the magnetically ordered phases of ErPb₃, HoPb₃, ErTl₃ and HoTl₃. The magnetic moments were found to be sinusoidally modulated with a propagation vector of (0, 0.2, 0.5) for the Pb-compounds and (0.38, 0.38, 0.16) for the Tl-compounds.Work supported by the Bundesministerium für Forschung und Technologie     

（LaO）3BO3中Eu^3＋和Sm^3＋的光致发光

研究了紫外光激发下，（ＬａＯ）３ＢＯ３基质中Ｅｕ＾３＋和Ｓｍ＾３＋的光谱性质，Ｅｕ＾３＋和Ｓｍ＾３＋的电荷迁移激发带及发光强度随组成和结构变化的规律性，并探讨了Ｅｕ＾３＋和Ｓｍ＾３＋自身浓度猝灭的机理。