Design of an efficient monochromatic electron source for inverse photoemission spectroscopy

A design for an efficient monochromatic electron source for Inverse Photoemission Spectroscopy(IPES)apparatus is described. The electron source consists of a Ba O cathode, a focus electrostatic lens, a hemispherical deflection monochromator(HDM), and a transfer electrostatic lens. The HDM adopts a "slit-in and slit-out" structure and the degradation of first-order focusing is corrected by two electrodes between the two hemispheres, which has been investigated by both analytical methods and electron-ray tracing simulations using the SIMION program. Through the focus lens, the HDM, and the standard five-element transfer lens, an optimal energy resolution is estimated to be about 53 MeV with a beam flux of 27 μA. Pass energy(P.E.) of 10 eV and 5 eV are discussed, respectively.     

Highly efficient beamline and spectrometer for inelastic soft X‐ray scattering at high resolution

The design, construction and commissioning of a beamline and spectrometer for inelastic soft X‐ray scattering at high resolution in a highly efficient system are presented. Based on the energy‐compensation principle of grating dispersion, the design of the monochromator–spectrometer system greatly enhances the efficiency of measurement of inelastic soft X‐rays scattering. Comprising two bendable gratings, the set‐up effectively diminishes the defocus and coma aberrations. At commissioning, this system showed results of spin‐flip, d–d and charge‐transfer excitations of NiO. These results are consistent with published results but exhibit improved spectral resolution and increased efficiency of measurement. The best energy resolution of the set‐up in terms of full width at half‐maximum is 108 meV at an incident photon energy tuned about the Ni L₃‐edge.     

单色仪定标曲线的非线性拟合简

采用两种方案对WDF棱镜单色仪的定标曲线进行非线性拟合。通过实验找出棱镜的折射率与TT鼓轮的关系,得到利用科希公式拟合定标曲线的可行性方案;利用高阶多项式对定标曲线进行拟合,运用统计的方法探讨不同的拟合阶数对拟合结果的影响,并得到了最佳的拟合阶数和高精度的拟合结果。     

前置平面镜热负载对变包含角平面光栅单色器分辨率的影响

针对变包含角平面光栅单色器前置平面镜（PM）受热负载而导致的单色器分辨率降低问题,提出优化聚焦常数（C_ff）补偿分辨率的方法。首先,计算不同C_ff值时PM的热功率吸收谱,在此基础上对镜面热负载进行热-结构耦合分析,得到不同热负载时PM表面热变形的变化量;然后,结合理想分辨率公式和光线追迹软件求出加热负载的单色器分辨率;最后,优化C_ff实现分辨率的补偿。研究结果表明,以软X射线谱学显微光束线站为例,当出射光能量为1 000 eV时,将C_ff由1.8优化至1.84,单色器分辨率即可与无热负载时的相同,该优化方法可有效补偿单色器分辨率的降低。     

The Intermolecular S?H⋅⋅⋅Y (Y=S,O) Hydrogen Bond in the H2S Dimer and the H2S–MeOH Complex

The nature of the S? H???S hydrogen‐bonding interaction in the H₂S dimer and its structure has been the focus of several theoretical studies. This is partly due to its structural similarity and close relationship with the well‐studied water dimer and partly because it represents the simplest prototypical example of hydrogen bonding involving a sulfur atom. Although there is some IR data on the H₂S dimer and higher homomers from cold matrix experiments, there are no IR spectroscopic reports on S? H???S hydrogen bonding in the gas phase to‐date. We present experimental evidence using VUV ionization‐detected IR‐predissociation spectroscopy (VUV‐ID‐IRPDS) for this weak hydrogen‐bonding interaction in the H₂S dimer. The proton‐donating S? H bond is found to be red‐shifted by 31 cm^?1. We were also able to observe and assign the symmetric (ν₁) stretch of the acceptor and an unresolved feature owing to the free S? H of the donor and the antisymmetric (ν₃) SH stretch of the acceptor. In addition we show that the heteromolecular H₂S–MeOH complex, for which both S? H???O and O? H???S interactions are possible, is S‐H???O bound.     

氢原子光谱实验的误差及其优化问题研究

主要介绍了利用精密光栅单色仪扫描氢原子光谱获得光谱波长,定性和定量地探究实验最佳条件的选择,对氢原子光谱实验进行误差分析,并提出优化改进方案,从而对学生实验进行指导,加深学生对近代物理的了解。     

Luminescent properties of (Y,Gd)BO3:Bi,RE (RE=Eu, Tb) phosphor under VUV/UV excitation

Bi³⁺- and RE³⁺-co-doped (Y,Gd)BO₃ phosphors were prepared and their luminescent properties under vacuum ultraviolet (VUV)/UV excitation were investigated. Strong red emission for (Y,Gd)BO₃:Bi³⁺,Eu³⁺ and strong green emission for (Y,Gd)BO₃:Bi³⁺,Tb³⁺ are observed under VUV excitation from 147 to 200 nm with a much broader excitation region than that of single Eu³⁺-doped or Tb³⁺-doped (Y,Gd)BO₃ phosphor. Strong emissions are also observed under UV excitation around 265 nm where as nearly no luminescence is observed for single Eu³⁺-doped or Tb³⁺-doped (Y,Gd)BO₃. The luminescence enhancement of Bi³⁺- and RE³⁺-co-doped (Y,Gd)BO₃ phosphors is due to energy transfer from Bi³⁺ ion to Eu³⁺ or Tb³⁺ ion not only in the VUV region but also in the UV region. Besides, host sensitization competition between Bi³⁺ and Eu³⁺ or Tb³⁺ is also observed. The investigated phosphors may be preferable for devices with a VUV light 147-200 nm as an excitation source such as PDP or mercury-free fluorescent lamp.     

BaMgAl_(10)O_(17)∶R~(2+)(R=Eu,Mn)的真空紫外光谱特性

采用高温固相反应法合成了BaMgAl10 O17∶R(R =Eu ,Mn)荧光体 ,测量了荧光体的真空紫外激发光谱和相应的发射光谱 ,观察到基质吸收带位于 16 5nm附近 ,Mn2 + 离子的吸收位于 170～ 2 40nm范围 ,Eu2 + 离子的 4f→ 5d吸收位于 2 10～ 40 0nm范围。真空紫外光谱特性的研究表明基质与激活离子之间存在较好的能量传递。     

大型光谱辐射计研制中的几个问题

本文是作者研制大型光谱辐射计中若干重要问题的初步总结。文中从理论和实践方面对光学系统、光栅参数的选取、狭缝形状和尺寸、波长扫描机构、入口出口系统以及装配调试等问题进行了简要的分析。这些分析和结论对类似的其他光谱仪器同样适用。