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1.
冰晶石类氟化物的红外光谱分析   总被引:2,自引:1,他引:1  
用傅里叶变换红外光谱法研究了K3AlF6,α-Rb3AlF6,β-Rb3AlF6和Cs3AlF6等注晶石类氟化物的远红外及中红外光谱,并对远红外光谱和部分中红外光谱带进行了指认。  相似文献   

2.
在成功制备C60外延薄膜的基础上,我们又尝试了碱金属Rb对该膜的掺杂。结果表明,从室温至80K左右,Rb3C60薄膜的电阻温度系数大于0,并近似符合公式:ρ(T)=a+bT^2,与单晶样品一致。但是,当温度低于80K以后,出现了弱的对数局域。在5K、零场下,样品的Jc值一般为10^3-10^4A/cm^2,且有如下规律:Jc(T)=Jc(0)(1-T/Tc)^a,α=1.3-2.0。此外,我们还测  相似文献   

3.
A3M2GeO12石榴石体系中Cr^3+离子的宽带发射光谱   总被引:1,自引:0,他引:1  
首次报道在A3M2Ge3O12:Cr(A=Cd^2+,M=Al^3+,Ga^3+,Sc^3+)锗酸盐石榴石体系中,Cr^3+离子室温下的红-近红外宽发射带光谱性质。随位于八面体格位上的Al^3+→Ga^3+→Sc^3+和十二面体格位上的Cd^2+→Ca^2+组成顺序变化,室温下,Cr^3+离子的^4T2→^4A2能级跃迁的R-NIR宽发射带,发射峰及光谱的长波和短波边逐渐向低能长波边移动。  相似文献   

4.
首次报告在A3M2Ge3O12∶Cr(A=Cd2+,Ca2+;M=Al3+,Ga3+,Sc3+)锗酸盐石榴石体系中,Cr3+离子室温下的红—近红外(R—NIR)宽发射带光谱性质。随位于八面体格位上的Al3+→Ga3+→Sc3+和十二面体格位上的Cd2+→Ca2+组成顺序变化,室温下,Cr3+离子的4T2→4A2能级跃迁的R-NIR宽发射带,发射峰及光谱的长波和短波边逐渐向低能长波边移动。这是由于晶场强度减弱,阳离子的离子半径增大的结果。在镉(钙)铝和镉(钙)镓锗酸盐体系中,少量Sc3+取代八面体上的Al3+和Ga3+时,可使Cr3+的R-NIR荧光发射强度增强。  相似文献   

5.
HIGHLYCHARGEDATOMICPHYSICSATHIRFL-CSRMaXinwenWangYoudeHouMingdongJinGengminInstituteofModernPhysics,AcademiaSinica,Lanzhou73...  相似文献   

6.
此文计算了Z=18-82的原子在北京同步辐射4B9A束线的白色X光照射下的光电离积分截面G值。结果表明,有三个G值较大的区域,Z=18-20,39-47和59-82,最大值分别为3.8×10-6,1.6×10-5和3.5×10-5photons·cm2/s。同时,估计了平衡时主要多重电荷态离子数目,分析了用同步辐射和离子阱进行多重电荷态实验的新的候选原子,讨论了有关实验方法和技术。  相似文献   

7.
本文用X射线衍射、傅里叶变换红外光谱、差热分析等物理方法研究了抗癌药物铂络合物特性、结构以及构效关系.研究结果表明:cis-[Pt(NH3)2Cl2]属简单斜方晶系,晶格常数a=0.9221nm,b=0.8771nm,c=0.6890nm.草酸二氨合铂的结构为斜方晶系,其晶格常数为:a1=1.0721nm,a2=0.6402nm,a3=1.8570nm,并用傅里叶变换红外光谱、差热分析、元素分析等方法对它们理化特性进行了研究  相似文献   

8.
Two-photonInducedUVFluorescenceinPhoto-activeSpiropyranMolecules¥CHILunguang;WANGZugeng(DepartmentofPhysics,EastChinaNormalUn...  相似文献   

9.
本文首次报导了生长温度为550℃,以三甲基镓(TMGa)和三甲基铟(TMIn)为Ⅲ族源,用低压金属有机物气相沉积(LFMOCVD〕技术,高质量1.62um和1.3umInGaAsP及In0.57Ga0.43As0.98P0.04/In0.73Ga0.27As0.6P0.4量子阶结构的生长,并给出了1.55umGaAsP/InP分别限制应变量子阱结构激光器的生长条件,激光器于室温下脉冲激射,其阈值电流密度为2.4kA/cm2。  相似文献   

10.
合成、鉴定了题示光敏离子载体(MMC-MAC(O5 ))。基于不同pH值水溶液中吸收和荧光光谱的变化, 计算得该试剂基态和激发态分子的酸性常数(pKa = 8.84, pKa = 5.11)。基于在不同溶剂中荧光光谱的变化, 由Solvachrom ic法, 借助Alchem y 2000 量化计算软件, 估算得该分子的基态和激发态偶极矩, 分别为3.11D和8.13D。同时发现, MMC-MAC(O5 )水溶液除氧后其荧光强度奇迹般地提高近20 倍, 并伴随一定强度的延迟荧光发射。其荧光或延迟荧光强度与浓度在一定范围内呈良好线性关系。检测限分别为2×10- 9和1.3×10- 8 m ol·L- 1 。  相似文献   

11.
High-pressure effects on the superconducting transitions of beta-pyrochlore oxide superconductors AOs(2)O(6) (A = Cs,Rb,K) are studied by measuring resistivity under high pressures up to 10 GPa. The superconducting transition temperature T(c) first increases with increasing pressure in every compound and then exhibits a broad maximum at 7.6 K (6 GPa), 8.2 K (2 GPa), and 10 K (0.6 GPa) for A = Cs, Rb, and K, respectively. Finally, the superconductivity is suppressed completely at a critical pressure near 7 GPa and 6 GPa for A = Rb and K and probably above 10 GPa for A = Cs. Characteristic changes in the coefficient A of the T(2) term in resistivity and residual resistivity are observed, both of which are synchronized with the corresponding change in T(c).  相似文献   

12.
We report the physical properties of the pseudo one dimensional ternary molybdenum chalcogenides M2Mo6X6 (M = K, Rb,Cs,Tl;X = Se, Te) measured on single crystals grown at high temperature. For Group IA metals (Rb,..,Cs) the transport properties evolve from a metallic to a semiconducting-like behavior on decreasing the temperature. Over the same temperature range the Group IIIA compound (Tl2Mo6Se6) remains metallic and even superconducts at 5.1K. The susceptibility of these materials is weakly diamagnetic and does not reveal anomalied correlated to the onset of the broad metal-nonmetal transition, except perhaps for Cs2Mo6Te6. A variation of the electronic interchain coupling is proposed to explain the difference between the Group IA and IIIA metal compounds. In the absence of evidence of three dimensional ordering at low temperature, we suggest that the broad metal-nonmetal transition is due to a fluctuating Pierls gap that is uncorrelated from one Mo chain to the next.  相似文献   

13.
A unique extremely thin cell (ETC) with the thickness of Cs atomic vapour layer in the range of 150–300 nm has been developed for the first time. All six hyperfine transitions of D2 line (852 nm) of Cs, i.e. 6S1/2(F=3)→6P3/2(F=2–4) and 6S1/2(F=4)→6P3/2(F=3–5) are very well resolved in the transmission and fluorescence spectra, whereas in a cell of usual length they are not resolved due to Doppler broadening. It is demonstrated that a robust and widely used simple laser-diode technique is enough to observe separately atomic hyperfine transitions at the intensity up to 100 mW/cm2 thanks to the ETC usage. We report also the first results obtained with the new ETC of 300 nm thickness filled with natural Rb. The usage of ETC allowed us to completely resolve each particular hyperfine transition of both 85Rb and 87Rb isotopes in D1 line fluorescence spectrum.  相似文献   

14.
The hexagonal Jahn-Teller compounds ABCl3 (A=Cs, Rb; B=Cu, Cr) in their common high temperature phase are modeled as a system of independent elastic dipoles dressed by a far reaching strain field. The diffuse elastic cross section for neutrons is derived as for Huang scattering. Isointensity contours and line widths (FWHM) are calculated for CsCuCl3 and compared to experimental results, especially looking for correlations and precursor effects of the structural phase transition.  相似文献   

15.
Accurate laser spectroscopic studies of the principal resonance transitions in Rb and Cs atoms embedded in liquid helium have shown appreciable line shifts and change in line profiles. A pilot attempt has been made here to compute ab-initio the spectral line shift of the resonance excitation lines in Rb under such a confinement. Relativistic density functional theory (RDFT) within local density approximation (LDA) has been adopted. A model cluster of fourteen helium atoms surrounding the central Rb is assumed. With an optimized radius of the cluster of 5.15 Å the RLDA estimate of the blue shift of the lowest 2S → 2P excitation line of Rb comes out to be 15.4 nm which compares very well with the experimental value of 16.4 nm.  相似文献   

16.
We report the production of a high phase-space density mixture of 87Rb and 133Cs atoms in a levitated crossed optical dipole trap as the first step towards the creation of ultracold RbCs molecules via magneto-association. We present a simple and robust experimental setup designed for the sympathetic cooling of 133Cs via interspecies elastic collisions with 87Rb. Working with the |F = 1,m F = +1〉 and the |3, +3〉 states of 87Rb and 133Cs respectively, we measure a high interspecies three-body inelastic collision rate ~10?25?10?26 cm6 ? s?1 which hinders the sympathetic cooling. Nevertheless by careful tailoring of the evaporation we can produce phase-space densities near quantum degeneracy for both species simultaneously. In addition we report the observation of an interspecies Feshbach resonance at 181.7(5) G and demonstrate the creation of Cs2 molecules via magneto-association on the 4(g)4 resonance at 19.8 G. These results represent important steps towards the creation of ultracold RbCs molecules in our apparatus.  相似文献   

17.
本文测定了Cs3Cu2 I5 晶体薄膜在室温及液氮温度下的吸收谱,并依此计算出该材料的激子参数,即激子束缚能ΔE(1)ex = (0.53±0.07)eV,激子半径aex = 0.326 nm ,禁带宽度Eg = (5.00±0.07)eV。在谱分析的基础上,论证了Cs3Cu2I5 的电子和激子激发定域在该晶体的CuI亚晶格之中,同时,揭示了在低温下Csx Cu1- x I系列化合物的第一激子峰位置随其摩尔组分变化的规律。  相似文献   

18.
We present a theoretical analysis of numerous magnetically tunable Feshbach resonances measured by Chin et al. [preceding Letter, Phys. Rev. Lett. 85, 2717 (2000)] at fields of up to 25 mT. This analysis provides the most accurate characterization of the collisional properties of ground state Cs atoms currently available and clearly shows, in contrast to previous work, that Bose-Einstein condensation of 133Cs cannot be ruled out. The X1Sigma(+)(g) and a(3)Sigma(u) scattering lengths are constrained to (280+/-10)a(0) and (2400+/-100)a(0), respectively ( 1a(0) = 0.052 917 7 nm), and the van der Waals C6 coefficient to 6890+/-35 a.u.(1 a.u. = 0.095 734 5 x10(-24) &Jdot;nm(6)).  相似文献   

19.
张星  张奕  张建伟  张建  钟础宇  黄佑文  宁永强  顾思洪  王立军 《物理学报》2016,65(13):134204-134204
报道了自行研制的894 nm高温垂直腔面发射激光器(VCSEL)以及基于此类器件的芯片级铯原子钟系统的应用实验结果.根据芯片级铯原子钟对VCSEL在特定高温环境下产生894.6 nm线偏振激光的要求,对器件的量子阱增益及腔模位置等材料结构参数进行了优化,确定增益-腔模失谐量为-15 nm,使器件的基本性能在高温环境下保持稳定.研制的VCSEL器件指标为:20—90?C温度范围内阈值电流保持在0.20—0.23 m A,0.5 m A工作电流下输出功率0.1 mW;85.6?C温度环境下激光波长894.6 nm,偏振选择比59.8:1;采用所研制的VCSEL与铯原子作用,获得了芯片级铯原子钟实施激光频率稳频的吸收谱线和实施微波频率稳频的相干布居囚禁谱线.  相似文献   

20.
We studied selective reflection (SR) of laser radiation from a window of a nanocell with thickness L ~ λ1,2/2 filled with Rb and Cs atoms, where λ1 = 780 nm and λ2 = 852 nm are the wavelengths resonant with the D2 laser lines for Rb and Cs, respectively. It is demonstrated that the negative derivative of the SR signal profile for L > λ/2 changes to the positive one for L < λ/2. It is shown that the real-time formation of the SR signal profile derivative (SRD) with the spectral width 30–40 MHz and located at the atomic transition is, in particular, a convenient frequency marker of D2 transitions in Rb and Cs. The amplitudes of SRD signals are proportional to the atomic transition probabilities. A comparison with the known saturated absorption (SA) method demonstrated a number of advantages, such as the absence of cross-over resonances in the SRD spectrum, the simplicity of realization, a low required power, etc. An SRD frequency marker also operates in the presence of the Ne buffer gas at a pressure of 6 Torr, which allowed us to determine the Ne–Rb collisional broadening, whereas the SA method is already inapplicable at buffer gas pressures above 0.1 Torr. The realization simplicity makes the SRD method a convenient tool for atomic spectroscopy. Our theoretical model well describes the SRD signal.  相似文献   

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