The effect of transition probability on the shape of X-ray photoelectron spectra of diamond and silicon

X-ray photoelectron spectra of valence bands in diamond and silicon have been calculated. It is shown that the probability of electron excitation from s-states is higher than that from p-states. The density of the electron states in the valence band of these crystals differs markedly from the energy distribution of photoelectrons.     

等离子体X射线吸收谱及发射谱研究

 报道计算高温高密等离子体吸收谱和发射谱（光学薄）的理论方法；该方法基于相对论原子理论，可以计算任何单元素以及多元素等离子体的谱分辨X射线吸收谱和发射谱（光学薄）；应用了量子亏损理论，可以减少计算量。利用该方法计算金等离子体LTE吸收谱，计算结果与实验符合良好。本文还对金等离子体LTE的光学薄发射谱进行了研究, 这将有利于对实验进行进一步的诊断分析。该理论计算方法还可提供等离子体内各电离度能级布居等重要物理参数。因此经“标准实验”检验的该理论计算方法将是提供ICF“精密”物理辐射参数的重要基础。     

等离子体X射线吸收谱及发射谱研究

报道计算高温高密等离子体吸收谱和发射谱（光学薄）的理论方法;该方法基于相对论原子理论,可以计算任何单元素以及多元素等离子体的谱分辨X射线吸收谱和发射谱（光学薄）;应用了量子亏损理论,可以减少计算量。利用该方法计算金等离子体LTE吸收谱,计算结果与实验符合良好。本文还对金等离子体LTE的光学薄发射谱进行了研究, 这将有利于对实验进行进一步的诊断分析。该理论计算方法还可提供等离子体内各电离度能级布居等重要物理参数。因此经“标准实验”检验的该理论计算方法将是提供ICF“精密”物理辐射参数的重要基础。     

X-ray emission spectra of small molecules

An instrument for X-ray emission studies of free molecules is described and electron and fluorescence excitations are discussed. The application of X-ray emission spectroscopy to free molecules is exemplified by the spectra of N₂, CO, NO and CO₂. From the spectra the core level binding energies of the molecules are deduced. For the diatomic molecules vibrational fine structure is resolved and analyzed in terms of different bond lengths in the initial and final states. The change in bond length, when the initial 1s vacancy is formed, is also discussed. The influence of the X-ray selection rules and molecular localization properties on the band intensities are discussed and exemplified by the O1s and C1s spectra of CO and CO₂. In the spectra about ten satellites are found.     

Simulations of resonant X-ray emission spectra of molecules

ab initio calculations. We let each molecule, or group of molecules, represent one particular aspect: calculations on molecular oxygen, benzene, carbon dioxide, aniline, fullerenes, chlorofluoromethanes, carbon monoxide, and polyenes are used to illustrate, in order, the effects of parity selection rules and core hole localization, vibronic coupling and symmetry breaking, frequency dependence of symmetry breaking, the role of chemical shifts, the character of band gap excited spectra, polarization anisotropies, the role of screening, and the role of excitons. Accepted: 6 March 1997     

类氢硅离子软X射线谱的计算

利用高剥离态类氢离子的势函数模型，计算了类氢Si离子的软X射线谱及 其精细结构，计算结果与实验值进行了比较。     

Radiative Auger emission in Ne K X-ray spectra

Radiative Auger emission intensity in K X-rays from neon was measured following electron bombardment by 1 to 2 keV electrons. The measured relative intensities of this process are in good agreement with calculations of Dyall using correlated final-state wavefunctions.     

The effect of the core hole on x-ray emission spectra in simple metals

We show that one-particle calculations of x-ray spectra with and without the core hole can give drastically different results, indicating a breakdown of one-particle theory. Only emission spectra obtained in the absence of the core hole consistently show a close resemblance to experiment. We show, that this fact can be explained by the many-body theory of Nozières and DeDominicis. We are then able to give the first interpretation of the L_2,3 satellite spectrum of sodium.     

Curved surface effect and emission on silicon nanostructures

The curved surface （CS） effect on nanosilicon plays a main role in the activation for emission and photonic manipulation. The CS effect breaks the symmetrical shape of nanosilicon on which some bonds can produce localized electron states in the band gap. The investigation in calculation and experiment demonstrates that the different curvatures can form the characteristic electron states for some special bonding on the nanosilicon surface, which are related to a series of peaks in photoluminecience （PL）, such as LN, LNO, Lo1, and Lo2 lines in PL spectra due to Si-N, Si-NO, Si=O, and Si-O-Si bonds on curved surface, respectively. Si-Yb bond on curved surface of Si nanostructures can provide the localized states in the band gap deeply and manipulate the emission wavelength into the window of optical communication by the CS effect, which is marked as the Lyb line of electroluminescence （EL） emission.     

温度对功率LED光谱特性的影响

制备了两种1 w白光功率发光二极管(LED),这两种样品分别是对台湾和美国两家公司生产的蓝光芯片,涂敷相同荧光粉和透明硅胶封装而成.对制备好的LED进行了变温光学特性测试,温度变化范围为15～75℃,测试电流为350 mA.结果表明:温度变化对LED的峰值波长,辐射通量、色温等参数都有影响.通过对光谱曲线的数据处理,找...     

The effects of high uniaxial stress on the far infra-red impurity spectra of high purity n- and p-type silicon

The stress dependence of the shallow impurity states of high purity n- and p-type silicon is studied by means of far infra-red spectroscopy up to a high stress limit, where the spectra observed are almost independent of the magnitude of the stress applied. In addition to the predicted behaviour, a small decrease in frequency of the 1s(B₂)-np_± series of donor lines is observed with a uniaxial <100> stress. A significant movement of the np₀ series relative to the np_± series is also detected. In the case of p-type silicon, the bands are decoupled with the result that the acceptor states at high stress are associated with a single band having oblate ellipsoidal energy surfaces. The spectrum with stress applied along a <111> direction is explained qualitatively by a first order variational calculation of the states concerned.     

K X-ray emission spectra from ν-Al2O3

Summary η-Al₂O₃ sample was bombarded with 12.5 keV electron.K X-ray spectra of this sample were compared with those of pure Al and α-Al₂O₃.     

Differential inverse inelastic mean free path determination on the base of X-ray photoelectron emission spectra

The photoelectron spectroscopy model is based on the solution of the radiative transfer equation with inner sources. The exact numerical solutions using BDF method are presented. PES, XAES and EELS spectra are described as series by the number of inelastic scatterings. Differential inverse inelastic mean free path for Be and W are obtained from the experimental data by the fitting procedure.     

Determining misorientation of graphite grains from the angular dependence of X-ray emission spectra

Angular-resolved X-ray absorption spectra were measured for pyrolytic graphite samples of various quality. A new approach to determining the misorientation of graphite grains in polycrystalline samples is proposed, which is based on calculations of the angular dependence of the relative intensity of a peak corresponding to the π* state for a normal distribution of grains. The experimental values are used to construct theoretical angular dependences using partial densities of the π* and σ* states determined from the nonempirical calculations for graphite.     

Energy band structure and X-ray emission spectra of ZrC and ZrN

Self-consistent augmented plane wave calculations are performed for ZrC and ZrN. The charge distributions resulting from valence bands in different regions of the unit cell are discussed and compared with related compounds, where the transition metal is varied between a 3d and 4d element of group IV and V. The limitations of the rigid band model are illustrated and general trends in the chemical bonding are discussed. In connection with X-ray emission spectra (XES) matrix element effects are shown for the three spectra Zr-L_III,-M_III, and-N_III. Further, comparison between theoretical and experimental XES is made with all data available for both ZrC and ZrN.     

The effect of high implant doses and high ion current densities on polyimide film properties

Ar⁺ and Ar²⁺ ions with energies of 40 and 80 keV are implanted into thin polyimide films. The implant doses and the ion current densities are varied in a wide range between 2.5×10¹⁴ and 1.5×10¹⁷ cm⁻² and between 1 and 16 μA/cm², respectively. The effect of the implantation parameters on the electrical, paramagnetic, and optical properties of the ion-modified near-surface polymer layer is studied. It is shown that the radiation-stimulated thermolysis of polyimide and its chemical constitution are responsible for a monotonic growth of the electrical conductivity of the layer with increasing ion current at a given implant dose. When the ion current density is fixed, the conductivity grows stepwise with implant dose, whereas the concentration of paramagnetic centers and the optical transmission of the modified layer decrease. The dependences observed are treated within a model of the structural reconfiguration of the polymer carbonized phase formed during the implantation.     

The fabrication of high quality silicon junction detectors by low energy ion implantation

High quality silicon junction detectors have been made by implantation of boron and phosphorus ions into silicon wafers. Resolutions of 20 keV for Po α-particles were obtained.     

X-ray Lα emission and LIII absorption spectra of copper compounds

The X-ray Lα _{1, 2} emission spectra and L_III absorption spectra in Cu, Cu₂O, CuCl, Cu₂S, CuO, CuCl₂, CuS, CuF₂ and Cu(en)₂Cl₂ are investigated. It is shown that the emission spectra of divalent copper compounds are considerably distorted due to a sharp absorption peak near the L_III edge. The nature of this peak is discussed and a relation is made with satellite peaks in X-ray photoelectron spectra.