用多步激发技术测定锶的(5p3/2ns)1及(5p3/2nd)3自电离谱

用分步激发方法及偏振光技术,测定了锶的(5p_3/2ns)₁(n=13-21)及(5p_3/2 nd)₃(n=13-24)各自电离谱,在低于5p_1/2电离限的(5p_3/2ns)₁态的实电子激发谱中,出现对应于(5p_1/2ns)₁及(5p_1/2nd)₁的畸变峰,畸变峰也出现于(5p_3/2nd)₃的实电子激发谱中。这说明(5p_jns)(5p_jnd)自电离系列间存在相互作用。 关键词：     

H3PAuPh与(H3PAu)2(1,4-C6H4)2光谱性质的密度泛函研究

用密度泛函(DFT)方法优化了配合物H₃PAuPh(a),(H₃PAu)₂(1,4-C₆H₄)₂(b)的基态的几何结构,并用含时密度泛函方法计算了它们的吸收光谱.结果表明配合物a与 b的最低能量吸收谱线的波长分别为257.5 nm和307.6 nm,皆具有C(2p)→Au(6p)电荷转移参与下的p_π 关键词： 激发态 光谱 密度泛函 3')" href="#">AuPH₃     

Li2K(IO3)3与Li2NH4(IO3)3的晶体结构

本文用X射线粉末法测定了Li₂K(IO₃)₃与Li₂NH₄(IO₃)₃的晶体结构和原子参数。发现Li₃K(IO₃)₃,Li₂NH₄(IO₃)₃与Li₂Rb(IO₃)₃同晶型,属单斜晶系,空间群为P2₁/α,每个单胞含有四个化合式量。室温的点阵常数分别为α=11.198?,b=11.046?,c=8.254?,β=111.53°,及α=11.327?,b=11.078?,c=8.341?,β=111.87°。讨论了二元化合物的形成与离子半径的关系。 关键词：     

钙钛矿(C6H5CH2NH3)2PbBr4拉曼光谱研究

运用激光拉曼光谱实验和密度泛函理论计算研究了450～1 700 cm-1光谱范围内有机-无机杂化钙钛矿材料(C₆H₅CH₂NH₃)₂PbBr₄的振动模式特性。对比实验所得拉曼光谱和理论计算所得拉曼光谱,发现密度泛函理论计算可以很好的模拟(C₆H₅CH₂NH₃)₂PbBr₄有机部分的分子振动模式。同时通过比较分析密度泛函理论计算和参考文献,对450～1 700 cm-1光谱范围内的拉曼峰的分子振动模式进行了初步的归属,并发现该光谱范围内的拉曼峰主要是由(C₆H₅CH₂NH₃)₂PbBr₄分子中有机部分振动所产生的。     

等离子体屏蔽效应对原子能级和振子强度的影响

利用Debye模型,研究了等离子体屏蔽效应对热等离子体中原子能级和振子强度的影响.通过在MCDF模型中引入等离子体屏蔽效应,计算了MnXXII-BrXXII等11个类Be离子在等离子体环境下2s²—［2s_1/2,2p_1/2］₁和2s²—［2s_1/2,2p_3/2］₁跃迁的能级和振子强度.计算结果表明,等离子体屏蔽效应使得类Be离子2s²—［2s_1/2,2p_1/2］₁跃迁的激发能量增大,从而导致谱线蓝移现象;并且随着屏蔽效应的不断增强,蓝移的程度会逐渐加大.屏蔽效应对于2s²—［2s_1/2,2p_3/2］₁跃迁的振子强度也有类似的影响. 关键词： Debye 等离子体屏蔽 跃迁能级 振子强度     

Fe(NH2trz)3·(BF4)2掺杂聚芴的有机电致发光器件

对于RGB有机电致发光器件(OLEDs),蓝光非常重要.在现有各种蓝光材料中,聚芴(PFO)非常稳定且荧光量子效率可达80%,但它有一个非常大的缺点:电致发光会产生异常绿光带.这严重影响了PFO相关器件的饱和色纯度.本文使用分子基磁性材料Fe(NH₂trz)₃·(BF₄)₂掺杂PFO方法,解决了这一难题.以ITO为衬底,制作了结构为ITO/PEDOT:PSS/PFO:Fe(NH₂trz)₃·(BF₄)₂/CsCl/Al的器件.报道了利用Fe(NH₂trz)₃·(BF₄)₂特殊的电子自旋态调制PFO的光电特性,实现了PFO的强烈纯正蓝光发射.详细研究了Fe(NH₂trz)₃·(BF₄)₂对PFO光电特性的影响.在4 V至9 V电压的偏置下,没有Fe(NH₂trz)₃·(BF₄)₂的器件,发出特别异常的绿光.然而,与此形成明显对照的是:Fe(NH₂trz)₃·(BF₄)₂掺杂的器件发出强烈的本征蓝光;PFO绿色发光带被成功压制;随着电压的变化,器件光谱的蓝光部分在整个EL谱所占比例没有改变.运用光电磁一体化测量技术,进一步研究了PFO掺杂Fe(NH₂trz)₃·(BF₄)₂器件的磁发光(MEL)和磁电导(MC)效应.发现PFO:Fe(NH₂trz)₃·(BF₄)₂和纯PFO薄膜内都没有激基缔合物产生.运用发光动力学理论,分析了Fe(NH₂trz)₃·(BF₄)₂阻断PFO异常绿光发射的机理.     

正磷酸盐晶体Ba3(PO4)2和Sr3(PO4)2高温拉曼光谱研究

测量了碱土金属正磷酸盐Ba₃(PO₄)₂和Sr₃(PO₄)₂常温及高温拉曼光谱, 对拉曼振动模式进行指认, 并分析了晶体拉曼振动光谱及晶体结构在高温下的变化. 在温度升高的过程中, 拉曼振动频率向低频移动且振动峰宽度展宽, 晶体中的P-O平均键长随温度升高而变长, 但O-P-O的键角并未发生变化. 晶体在900 ℃以下无结构相变发生. 关键词： 3(PO₄)₂和Sr₃(PO₄)₂')" href="#">Ba₃(PO₄)₂和Sr₃(PO₄)₂ 高温拉曼光谱 振动模式 高温结构     

水热法制备的Li4-3xEux(MoO4)2微晶及其发光性能

采用水热法制备了Li_4-3xEu_{x(MoO4)2系列红色荧光粉.通过X射线衍射(XRD)、扫描电镜(SEM )和荧光分析(FL)对产物的微结构、形貌和发光性能进行表征分析.XRD分析表明,制备的Li4-3xEux(MoO4)2微晶均为白钨矿四方结构.SEM结果显示:随着x的增大,Li4-3xEux(MoO4)2微晶的晶粒尺寸相应减小,在0.2~0.5 μm之间变化.荧光分析结果表明:源于Eu³⁺的⁵D0→⁷F2和⁵D0→⁷F1电荷转移的592 nm和614 nm的特征发射峰显现明显,后者的发射强度远远大于前者.随着x的增大,样品中Eu³⁺的两个特征发射峰的强度先增大后减小,在x=1.0时达到最大.}     

超声冷却SO2( 1A2— 1A1)激光诱导荧光激发谱的转动分析

通过改变SO₂/Ar配比，研究了超声膨胀冷却SO₂( ¹A₂— ¹A₁)系统315—330nm波段振动分辨的激光诱导荧光(LIF)激发谱.获得了属于两个完整带系(1,m,1),(0,n,1)—(0,0,0)的高分辨转动结构谱.其中(ν′₁,ν′₂,ν′₃)=(0,9,1),(0,10,1),(1,7,1),(1 关键词：     

La1.6(MoO4)3:Eu0.43+纳米晶合成及发光特性

采用燃烧法合成了La_1.6(MoO₄)₃:Eu_0.4³⁺纳米晶末,研究了其声子-掺杂-晶格相互作用和发光性质.X射线粉末衍射(XRD)分析表明,在500~900 ℃退火后,La_1.6(MoO₄)₃:Eu_0.4³⁺样品为单一晶相.对样品进行了光致发光(PL)测量,激发Mo⁶⁺-O^2-电荷迁移带,观察到Eu³⁺的系列发光,表明Mo⁶⁺-O^2-带和Eu³⁺间存在能量传递,中心波长分别在λ₁=469 nm和λ₂=426 nm处的两个one-phonon边带,相应的声子能量分别为767和1202 cm^-1,分别对应于 Mo=O 和Mo-O-Mo伸缩振动.同时,计算了两个局域模电子-声子耦合强度的黄昆因子分别为S₁=0.055和S₂=0.037,为揭示其三价离子高传导特性及其负热膨胀物理特性提供了实验基础.     

STUDY OF BRANCHING RATIONS OF 3p3/2nd (J=1,3) AUTOIONIZING SERIES OF NEUTRAL MAGNESIUM

With the K matrix and multichannel quantum defect theory, we have studied the branching ratios of 3p_3/2nd (J=1,3) autoionizing series of Mg above the 3p_1/2 ion limit. The calculations are compared with the previous experimental spectra, and the unmeasured branching ratios are presented. The conclusion is that 3p_3/2nd state prepared by the three-step excitation can form population inversion between the 3p_1/2 and 3s_1/2 ionic states.     

Sr原子5p1/2ns系列自电离谱的观察和测定

本文报道了用孤立实激发的方法,对Sr的5p_1/2ns系列自电离谱的观察。测定了Sr的5p_1/2ns系列八个态的能级、量子亏损和线宽。 关键词：     

机械合金化La0.7Ca0.3MnO3的晶化动力学及磁电阻研究

通过机械合金化方法制备了单相La_0.7Ca_0.3MnO₃化合物.球磨形成的非晶态结构在920K退火时转变为钙钛矿型相结构.根据质量作用定律,讨论了非晶晶化动力学行为,其晶化转变激活能约为265kJ/mol.同时研究了化合物的电阻特性,发现低温下样品的电阻ρ与温度T的关系为ρ∝T²,随退火温度的升高,ρ-T²曲线斜率下降.在远离居里温度处的低温磁电阻可用Δρ/ρ₀=p₁-p₂T^3/2-p₃T描述. 关键词：     

CeO2/Nb2O5界面效应对提高CeO2氧敏特性的XPS研究

用射频/直流磁控溅射法制备了CeO₂/Nb₂O₅双层氧敏薄膜，利用X射线光电子能谱(XPS)，描述并解释了单层CeO₂薄膜中氧随温度变化的动力学行为，以及CeO₂/Nb₂O₅薄膜界面对氧敏特性的影响.通过对Ce3d XPS谱的高斯拟合，计算了Ce³⁺浓度并给出了判定Ce⁴⁺还原的标志.结果表明，界面效应可以提高CeO₂/Nb₂O₅薄膜中Ce⁴⁺的还原能力，使之远远高于单层CeO₂薄膜，这对薄膜的氧敏特性是极为有利的. 关键词：     

Vacuum ultraviolet reflectivity of crystalline LaF3 and PrF3

The reflectivity of single crystals of LaF₃ and PrF₃ has been measured using synchrotron radiation. Transitions of the types Pr 4f-5d, fluorine 2p-conduction band and lanthanide 5p-conduction band have been identified. The latter give rise to a number of sharp peaks in the 20–25 eV region which may be excitonic in origin.     

Emission features of Ho ion in Nb2O5, Ta2O5 and La2O3 mixed Li2O-ZrO2-SiO2 glasses

Li₂O-ZrO₂-SiO₂: Ho³⁺ glasses mixed with three interesting d-block elemental oxides, viz., Nb₂O₅, Ta₂O₅ and La₂O₃, were prepared. Optical absorption and photoluminescence spectra of these glasses have been recorded at room temperature. The luminescence spectra of Nb₂O₅ and Ta₂O₅ mixed Li₂O-ZrO₂-SiO₂ glasses (free of Ho³⁺ ions) have also exhibited broad emission band in the blue region. This band is attributed to radiative recombination of self-trapped excitons (STEs) localized on substitutionally positioned octahedral Ta⁵⁺ and Nb⁵⁺ ions in the glass network. The Judd-Ofelt theory was successfully applied to characterize Ho³⁺ spectra of all the three glasses. From this theory various radiative properties, like transition probability A, branching ratio β_r and the radiative lifetime τ_r, for ⁵S₂ emission levels in the spectra of these glasses have been evaluated. The radiative lifetime for ⁵S₂ level of Ho³⁺ ions has also been measured and quantum efficiencies were estimated. Among the three glasses studied the La₂O₃ mixed glass exhibited the highest quantum efficiency. The reasons for such higher value have been discussed based on the relationship between the structural modifications taking place around the Ho³⁺ ions.     

X-ray L1, L2 and L3 absorption limits of 4D transition metals

The wavelengths and energies of the L₁, L₂ and L₃ absorption limits in Zr, Nb, Ru, Rh, Pd and Ag metals have been measured and some of the previous reported values have been found to be incorrect. By comparing the energies of the absorption limits with those of the Lγ₁Ly, and Lβ_2,15, lines and also with the binding energies obtained by XPS, the electronic transitions corresponding to the respective absorption limits have been clarified. It is concluded that (i) the end level of the electronic transition corresponding to the L₁ absorption limit of Zr-Ag is the 5p-like level, and (ii) the end level corresponding to either of the L₂ and L₃, absorption limits of Zr-Pd is the 4d level, while that of Ag is, rather unexpectedly, the top of the 5s level.     

High resolution XPS study of the large-band-gap semiconductor stibnite (Sb2S3): Structural contributions and surface reconstruction

Conventional X-ray photoelectron spectroscopy (XPS) and synchrotron radiation XPS (SRXPS) were used to probe the chemical state properties of stibnite (Sb₂S₃), a large-band-gap semiconductor of complex structure. The conventional spectra were obtained with a Kratos Axis Ultra XPS with magnetic confinement charge neutralization, which is very effective in minimizing both uniform charging and differential charging on this large-band-gap semiconductor. The narrow linewidths (much narrower than previously obtained) for single doublet fits (e.g. Sb 4d_5/2 of 0.57 eV and S 2p_3/2 of 0.63 eV) enabled the observation of a small peak on the low binding energy side of the Sb 3d and Sb 4d lines. With the aid of the very surface-sensitive Sb 4d SRXPS spectra, these low energy peaks are assigned to small Sb metal clusters at the surface after cleavage; the signal for these clusters increases with X-ray dose on the sample.A detailed analysis of the Sb 4d and S 2p linewidths concludes that the Sb 4d_5/2 linewidth is larger than expected based on the inherent linewidth of the instrument and the Sb 4d lifetime width, and on comparison with the As 3d linewidth (0.52 eV) for the analogous As₂S₃. Also, the S 2p_3/2 linewidth is substantially broader than the Sb 4d_5/2 linewidth. These larger than expected linewidths are due to two structurally distinct Sb atoms and three structurally distinct S atoms in the Sb₂S₃ crystal structure. Accordingly, the Sb 4d and S 2p spectra have been fitted to two and three doublets respectively, and the linewidth for all peaks is 0.53 eV. Using recent molecular orbital calculations, the doublets have been assigned to the different structural Sb and S sites.     

A study of the 14N(d,p)15N reaction at low bombarding energies

Absolute differential cross sections of the proton groups p₀, p₁ + p₂, p₃, p₄ and p₅ from the ¹⁴N(d, p)¹⁵N reaction have been determined at bombarding energies between 0.309 and 0.638 MeV. The shape of the measured angular distributions are generally well reproduced by the incoherent sum of the contributions of direct and compound nucleus processes calculated with the distorted wave Born approximation and the Hauser-Feshbach formula respectively. However, a reliable value for the spectroscopic factor can be extracted only for the p₅ transition whose mechanism even at this energy is almost entirely direct.