EuB6的光电导率和能量损失函数谱的理论指认

基于更高精度的能带结构计算结果, 计算EuB6的光电导率和能量损失函数谱, 结果与实验一致. 通过具体计算找出在0-40 eV能量区间内所有可能发生的能带间电子跃迁, 在第一布里渊区中发生跃迁的区域和跃迁概率, 得到了各电子跃迁的始态和末态的单电子波函数. 利用计算结果详细分析了光电导率和能量损失函数各谱峰与能带间电子跃迁的联系. 在此基础上对实验测得的谱峰作出指认, 证实了Kimura等人根据实验结果所作经验指认的合理部分, 指出其中一些不准确的指认, 并补充了他们没有考虑到的一些对谱峰有重要贡献的电子跃迁.     

EuB6的能带结构与成键及其光学常数的计算

采用密度泛函方法研究了EuB6的电子结构, 得到高精度能带结构和态密度分布信息; 分析成键情况, 从原子间轨道相互作用的角度说明EuB6能带结构的特征及其半金属性质. 计算出EuB6的介电函数、反射率、光电导率和能量损失函数谱等, 与实验结果一致, 表明了能带计算获得的电子结构信息的可靠性.     

纳米稀土-介质薄膜光电发射光谱和能带结构

用真空蒸发沉积的方法制备了纳米稀土(La、Nd、Sm)粒子-BaO介质薄膜.研究表明薄膜的光电发射光谱响应阈值受纳米稀土粒子形状和大小的影响,球形纳米稀土(Sm)粒子-BaO介质薄膜的光谱响应阈值波长为720nm,条状纳米稀土(La和Nd)粒子-BaO介质薄膜阈值波长分别为650nm和660nm.研究得到纳米稀土粒子-介质薄膜等效界面位垒高度在1.7～2.0eV之间.由于纳米稀土粒子与BaO介质各自逸出功不同,当构成薄膜后使得纳米粒子周围的空间电荷分布发生变化,纳米粒子周围的能带发生弯曲.     

纳米稀土-介质薄膜光电发射光谱和能带结构

用真空蒸发沉积的方法制备了纳米稀土(La、Nd、Sm)粒子 BaO介质薄膜.研究表明薄膜的光电发射光谱响应阈值受纳米稀土粒子形状和大小的影响,球形纳米稀土(Sm)粒子 BaO介质薄膜的光谱响应阈值波长为720 nm,条状纳米稀土(La和Nd)粒子 BaO介质薄膜阈值波长分别为650 nm和660 nm.研究得到纳米稀土粒子 介质薄膜等效界面位垒高度在1.7～2.0 eV之间.由于纳米稀土粒子与BaO介质各自逸出功不同,当构成薄膜后使得纳米粒子周围的空间电荷分布发生变化,纳米粒子周围的能带发生弯曲.     

具有类白钨矿结构的KGd(MoO_4)_2的晶体结构和能带结构(英文)

以Gd2O3、K2CO3、MoO3为原料,采用高温熔盐法,合成了一个含钾的稀土钼酸盐KGd(MoO4)2。通过X射线单晶衍射法测定了它在室温下的晶体结构,并测定了它的光学性质。结构分析表明它属于三斜晶系,空间群为P1,a=0.529 23(6)nm,b=0.692 10(6)nm,c=1.068 89(7)nm,α=75.79(8)°,β=76.79(5)°,γ=67.60(4)°,Z=2,R1(all data)=0.025 8。结构中的K和Gd原子位于各自的晶体学位置,不存在调制结构的现象。此外,我们用得到的晶体学数据,通过密度泛函理论研究了化合物的能带结构、态密度、介电常数,其结果和实验数据相吻合。     

具有类白钨矿结构的KGd（MoO4）2的晶体结构和能带结构

以Gd₂O₃、K₂CO₃、MoO₃为原料,采用高温熔盐法,合成了一个含钾的稀土钼酸盐KGd（MoO₄）₂。通过X射线单晶衍射法测定了它在室温下的晶体结构,并测定了它的光学性质。结构分析表明它属于三斜晶系,空间群为P1,a=0.52923（6）nm,b=0.69210（6）nm,c=1.06889（7）nm,α=75.79（8）°,β=76.79（5）°,γ=67.60（4）°,Z=2,R₁（alldata）=0.0258。结构中的K和Gd原子位于各自的晶体学位置,不存在调制结构的现象。此外,我们用得到的晶体学数据,通过密度泛函理论研究了化合物的能带结构、态密度、介电常数,其结果和实验数据相吻合。     

掺杂聚苯胺能带结构和导电机理的研究

用EHMO-CO方法对质子掺杂聚苯胺进行了模型化理论计算,得到与吸收光谱实验数据一致的能带结构,研究表明,掺杂苯胺中的载流子是极化子,能满意地解释掺杂聚苯胺的导电机制。     

g-CN体系的准粒子能带结构和光学特性

利用多体格林函数理论,本文研究了二维CN体系(包括triazine和tri-s-triazine)的激发态特性。通过GW方法,我们计算了准粒子的能量。考虑电子-空穴相互作用,通过求解Bethe-Salpeter方程,我们获得了激发态能量和光谱。我们发现,在这两种CN体系的价带中,σ轨道和π轨道之间的交换作用非常强烈。由于占据的σ轨道和π轨道之间的准粒子修正量非常不同,因此,为了得到准确的带隙值和光谱,我们需要对这两种轨道开展精确的GW计算。与单层的CN体系相比,双层结构中层与层之间的范德华相互作用使带隙值降低了0.6 eV,而光吸收谱红移了0.2 eV,这是由于双层结构具有更小的激子束缚能。我们计算的吸收峰的位置与实验结果符合很好。实验中的吸收峰主要是由深能级的π轨道到π^*轨道的跃迁形成的。π→π^*跃迁和σ→π^*跃迁之间的耦合能够在长波长范围产生弱的吸收尾巴,如果调整入射光的极化方向,由σ→π^*跃迁产生的高强度的吸收峰将会在更低能量处出现。     

反式聚苯乙炔的光电导

聚苯乙炔(PPA)是一种共轭高分子材料,具有较好的光电导性能。因反式PPA比顺式具有较高的光暗比,本文研究了反式PPA的光导和暗导特性,得到的光、暗导曲线基本平行,说明本征载流子和光生载流子的输运机制是相似的。在欧姆区的光导和暗导的活化能分别为0.24±0.03eV和0.58±0.03eV。     

Ca2B2O5的电子结构和能带结构

合成了标题化合物,在已测晶体结构的基础上,利用含组态作用的INDO/S方法计算了其他电子能带结构;利用态求和方法计算了微结构分子的线性极化率及其晶体的平均折射率。分析结果表明,价带主要由B^3^+和O^2^-离子的价轨道的贡献,导带底部主要由Ca^2^+离子轨道的贡献,从O^2^-离子到Ca^2^+离子的电荷转移对线性极化率起主要贡献。     

Theoretical Assignments of the Optical Conductivity and Energy-loss Function Spectra of EuB6

On the basis of the calculated band structure of EuB6, with a higher accuracy, the optical conductivity and energy-loss function spectra were calculated, and the results were in good agreement with the experiments. All possible interband electronic transitions, the points in the first Brillouin zone where the transitions took place, and the transition probability were figured out through specific calculations. The wave functions of the initial and final states related to individual transitions were obtained as well. The calculated results were used to analyze, in detail, the correlation between the spectral peaks and the interband electronic transitions. On the basis of this, the experimental spectra were assigned, confirming the reasonable part of the empirical assignments given by Kimura et al. and pointing out the inaccurate part, and also supplying some electronic transitions, which made an important contribution to the spectral peaks, but had not been considered by Kimura et al.     

Growth, Band Structure and Optical Properties of LiSrBO3 Crystal

The bulk crystal of LiSrBO3 (8.39 g) with a size of 21mm×20mm×15mm was grown by high temperature solution growth method. The relationship between growth habit and crystal structure was discussed. The transmission spectrum shows an UV absorption edge at about 300 nm. The melting temperature of this crystal was determined to be 942 ℃ by DTA-TG measurement. The band structure of the LiSrBO3 crystal was studied by means of the first principle method. An indirect band gap was found to be about 4.0 eV,and a low dielectric constant was estimated to be about 1.9 in terms of theoretical results.     

蒙古药阿木日－6中金属元素的原子光谱分析

测定了常用蒙古药阿木日－６中金属元素的含量，为将来进一步探讨该药中金属元素，特别是微量元素与其药效的关系以及准确检验此种药物提供了实验数据．     

Synthesis, Crystal Structure and Band Structure of EuMg6Sn3.67

EuMg6Sn3.67 has been synthesized by reacting the mixture of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction study. EuMg6Sn3.67 crystallizes in hexagonal space group P63/m (No. 176) with a = 11.7259(4), c = 4.5507(2), V = 541.88(4)3 , Z = 2, Mr = 734.60, Dc = 4.502 g/cm3 , μ = 14.348 mm-1 , F(000) = 638, the final R = 0.0128 and wR = 0.0378 for 464 observed reflections with Ⅰ > 2σ(Ⅰ). EuMg6Sn3.67 is closely related to the Ba2Mg12Ge7.33 structure type and features a three-dimensional Mg6Sn3.67 framework with one-dimensional hexagonal tunnels along the c-axis occupied by the Eu atoms. Electronic structure calculation indicates that the title compound is metallic.     

Growth and Optical Properties of Sr_6YbSc(BO_3)_6 Crystal

1INTRODUCTION As is well known,the Yb3 ion has some advan-tages in comparison with Nd3 as laser active ion,for it has only two manifolds,i.e.,the ground2F7/2state and the excited2F5/2state.There is no excited state absorption reducing effective laser cross-section,no concentration quenching,no up-conversion,and three or four times longer emission lifetime than Nd3 ion.Yb3 ion exhibits a strong and broad ab-sorption band at ca.970nm and can be easily pumped with InGaAs diode lasers.The …     

Synthesis,Molecular Structure,Optical Properties and Electrical Conductivity of Zwitterionic Ferrocenyldithiophosphonates

Ferrocenyldithiodiphosphetane [FcPS(μ‐S)]₂ [Fc = Fe(η⁵‐C₅H₄)(η⁵‐C₅H₅)] reacts with the aminoethanol derivatives 1‐ethyl‐3‐pyrrolidinol and 2‐(piperazin‐1‐yl)ethanol to give the zwitterionic (O‐ethylammonium)ferrocenyldithiophosphonates ( 2 ) and ( 3 ), which were fully characterized by elemental analysis, IR and NMR spectroscopy and mass spectrometry. The optical and electrical properties of 2 and 3 as well as those of the previously reported [FcP(S)S(OC₂H₄NHEt₂)] ( 1 ) were studied. A molecular structure determination of 1 is also reported.     

染料中间体溴代硝基苯胺的结构鉴定和HPLC分析

本文提出测定4-溴-2-硝基苯胺(1)及其副反应产物的高效液相色谱(HPLC)分析方法。用紫外光谱、红外光谱、核磁共振氢谱鉴定(1)及副产物4,6-二溴-2-硝基苯胺(2)的结构。高效液相色谱采用的色谱柱为CLC-Ph柱(φ6×150mm),流动相为甲醇-水(70:30),测定的变异系数对于(1)和(2)分别为0.45%和1.07%,回收率分别为99.5%和99.7%。     

Synthesis and Crystal Structure of 6—Bromo—piperonal—dimethyl—acetal

1 INTRODUCTION 6-Bromo-piperonal-dimethyl-acetal is an intermediate used for the synthesis of natural products, such as podophyllotoxin[1] and the related compounds[2～6] due to the useful biological activities associated with some of its derivatives[7, 8]. In particular, glycoside derivatives of 4?dimethyl- 4-epipodophyllotoxin have been used in cancer chemotherapy[9, 10]. The title compound has been synthesized from raw material piperonal, after bromo substitution and acetal protection…