K_3C_(60)在200K附近的取向相变机理

研究了K3C6 0 单晶薄膜在 2 0 0K附近的导带结构 .样品温度为 190K时 ,同步辐射角分辨光电子谱能够观察到[111]方向有规律的能带色散 .而在 2 2 0K附近色散不存在 .这一实验结果与K3C6 0 在 2 0 0K存在取向相变相符合 .用反铁磁Ising模型对实验结果进行了分析 .结果表明 ,K3C6 0 在 2 0 0K的相变是由低温下的一维无序取向结构转变为2 0 0K以上的双取向结构畴与无序分子 (约占 40 % )的混合     

乙烯在Ru(1010)表面价带电子特性研究

在200K以下乙烯(C2H4)可以在Ru(1010)表面上以分子状态稳定吸附,200K以上乙烯发生了脱氢分解反应生成乙炔(C2H2).乙烯分解生成乙炔后,σCC和σCH分子轨道能级向高结合能方向分别移动了0.5和1.1 eV.偏振角分辨紫外光电子谱(ARUPS)结果表明:在Ru(1010)表面上,乙烯和脱氢反应后生成的乙炔分子的C-C键轴都不平行于表面,而是沿表面(0001)晶向倾斜.     

Detection of Fe 3d electronic states in the valence band and magnetic properties of Fe-doped ZnO film

Fe-doped ZnO film has been grown by laser molecular beam epitaxy(L-MBE) and structurally characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM),all of which reveal the high quality of the film.No secondary phase was detected.Resonant photoemission spectroscopy(RPES) with photon energies around the Fe 2p-3d absorption edge is performed to detect the electronic structure in the valence band.A strong resonant effect at a photon energy of 710 eV is observed.Fe3+ is the only valence state of Fe ions in the film and the Fe 3d electronic states are concentrated at binding energies of about 3.8 eV and 7 eV～8 eV.There are no electronic states related to Fe near the Fermi level.Magnetic measurements reveal a typical superparamagnetic property at room temperature.The absence of electronic states related to Fe near the Fermi level and the high quality of the film,with few defects,provide little support to ferromagnetism.     

弧光放电法原位清洗光学元件

光学元件受到污染后其光学性能会变差，如何对其进行清洗，尽可能地恢复其原来的性能，使其能够重新使用显得很重要。本文介绍—种碳污染的原位清洗方法——射频弧光放电法，利用原子氧与光学元件表面所沉积的碳反应以达到清洗的目的。清洗装置建立后对北京同步辐射装置（BSRF)上所使用的光学元件进行了清洗，取得了较好的效果。     

489B束线低能分支的性能改进

分析了北京同步辐射实验室489B原束线低能分支的构造及弊病，在不影响束线高能分支性能及总体机械结构的基础上提出了改进方案，详细介绍了该设计方案和光束线调试工作及出光后束线的性能测试工作，该测试结果完全符合束线的设计，该束线在同步辐射专用光实验中充分发挥了改进后的优势，取得了令人满意的结果。     

4B9B束线低能分支的性能改进

分析了北京同步辐射实验室4B9B原束线低能分支的构造及弊病,在不影响束线高能分支性能及总体机械结构的基础上提出了改进方案.详细介绍了该设计方案和光束线调试工作及出光后束线的性能测试工作,该测试结果完全符合束线的设计.该束线在同步辐射专用光实验中充分发挥了改进后的优势,取得了令人满意的结果     

Temperature effect on the electronic structure of Nb:SrTiO3 (100) surface

The effect of temperature on the electronic structure of Nb-doped SrTiO_3(100) surface is investigated by highresolution synchrotron radiation photoemission spectroscopy.According to the x-ray photoemission spectroscopy(XPS)results,at an annealing temperature of less than 700 ℃,the adsorbed carbon and hydroxyl on the STO surface could be removed,to expose the fresh intrinsic surface with a constant ratio of Ti/O.It is obvious that the STO would be doped by Ca~+ impurities of bulks and O vacancies in the surface after annealing at 920 ℃ for one hour.     

利用LMBE生长BaTiO3薄膜及其原位光电子能谱测量

利用激光分子束外延系统, 在STO:Nb衬底制备了高质量的BaTiO3单晶薄膜, 并在 北京同步辐射站4B9B对其进行了原位的光电子能谱的测量. XPS测量表明, 所生长的薄膜没有Ti离子变价. 实验中测得的价带谱与用ab initio方法计算的结果一致.     

乙烯在Ru( )表面价带电子特性研究

在200K以下乙烯（C2H4）可以在Ru（1010^-）表面上以分子状态稳定吸附,200K以上乙烯发生了脱氢分解反应生成乙炔（C2H2）。乙烯分解生成乙炔后,σCC和σCH 分子轨道能级向高结合 能方向分别移动了0.5和1.1eV。偏振角分辨紫外光电子谱（ARUPS）结果表明：在Ru(10106-)表面上,乙烯和脱氢反应后生成的乙炔分子在C－C键轴都不平行 于表面,而是沿表面<0001>晶向倾斜。     

Self-assembly and photoelectric properties of cerium complexes with 3,4,9,10-perylenetetracarboxylic acid on nanocrystalline TiO_2 films

Self-assembled (SA) films (PMP, M = Ce3+ or Ce4+) of 3,4,9,10-perylenetetracarboxylic acid (PTA) on nanocrystalline TiO2 films with Ce3+ or Ce4+ as a bridge were fabricated and characterized with UV-Vis, IR, and XPS synchrotron radiation photoelectron spectroscopy (SRPES) which gave the HOMO energy levels for the SA films. It was shown that thin-layer sandwich-type solar cells based on these SA films possess good properties for photoelectric conversion. While PTA-loaded TiO2 electrode (P) generated 26.9% of incident monochromatic photon-to-electron conversion efficiency (IPCE), PMP-sensitized Ti02 electrodes yielded 55.8% and 39.1% for Ce4+ and Ce3+ respectively. PMP films can be considered as a kind of complexes whose HOMO energy levels were proved to be higher than that of film P, which is one of the major reasons for the increase in IPCE from film P to film PMP.