Theoretical studies on the photoionization cross-sections of solid silver

An alternative expression for photoionization cross-section of atoms or molecules and a dielectric influence function （DIF） in a high-density system proposed recently are used to study the photoionization cross-sections of solid silver. It is suggested that a density turning point （DTP） of a photoionized system may be viewed as the critical point where the photoionization properties of atoms in a real system may have a notable change. The results show that the present theoretical photoionization cross-sections are in good agreement with the experimental results of a silver crystal both in structure and in magnitude.     

苯低压热解的光电离质谱和动力学模型 (cited: 3)

研究苯在30 Torr和1360～1820 K下的热解过程．利用同步辐射真空紫外光电离质谱技术对热解产物进行了检测,并对其随温度变化的摩尔分数曲线进行了测量．建立了一个低压苯热解动力学模型,并结合生成速率分析展示了燃料分解和芳烃生长过程中的主要反应网络．结果显示苯的分解主要通过氢提取反应生成苯基进行,部分通过单分子解离反应生成丙炔基或苯基进行,并终止于乙炔、丁二炔及1,3,5-己三炔等具有高热稳定性的聚炔烃类物种的生成．此外,低压苯热解中的芳烃生长过程起始于苯和苯基,并主要受到偶数碳增长机理控制．这是由于奇数碳增长机理所依赖的C5和C7物种在低压苯热解中很难生成．     

Synchrotron radiation VUV double photoionization of CHF2Cl

VUV double photoionization of CHF₂Cl in an energy region 32–40 eV was investigated with photoionization mass spectroscopy by using synchrotron radiation. The double ionization energy of CHF₂Cl and appearance energies for its main fragment dications (CHCl²⁺, CF₂²⁺ and CHFCl²⁺), were determined with photoionization efficiency spectroscopy for the first time. The single point energies of CHF₂Cl and its parent dication (CHF₂Cl²⁺) were calculated using Gaussian 03 program and density functional theory (DFT and B3LYP functional). The vertical double ionization energy of CHF₂Cl was predicted by using B3LYP method and empirical equation. According to our research results, the experimental double ionization energy of CHF₂Cl is in good agreement with the theoretically calculated vertical double ionization energy. The mechanism of double photoionization of CHF₂Cl was discussed based on the comparison of our experimental results with those predicted theoretically.     

Influence of Vibrational Excitation on Stereodynamics for O(3P)+D2→OD+D Reaction

Theoretical investigations on the stereodynamics of the O(³P)+D₂ reaction have been calcu-lated by means of the quasi-classical trajectory to study the product rotational polarization at collision energy of 104.5 kJ/mol on the potential energy surface of the ground ³A" triplet state. The vector properties including angular momentum alignment distributions and four polarization dependent generalized differential cross-sections of product have been presented. Furthermore, the influence of reagent vibrational excitation on the product vector properties has also been studied. The results indicate that the vector properties are sensitively affected by reagent vibrational excitation.     

Diagrammatic Representation of Electronic Correlations in Photoionization Process: Application to Scandium

The conversion rules under which an algebraic expression can be obtained from a corresponding photoionization Goldstone diagram have been given systematically in the present work. The electronic correlations in the photoionization processes then could be studied diagrammatically. The application to atomic scandium shows that the present theoretical scheme can give reasonable photoionization cross sections, which agree well with the experimental results.     

Evaluation of the atmospheric pressure photoionization source for the determination of benzidines and chloroanilines in water and industrial effluents by high performance liquid chromatography-tandem mass spectrometry

A solid phase extraction-high performance liquid chromatography-tandem mass spectrometry based analytical method suitable for simultaneous analysis of benzidine, 3,3′-dichlorobenzidine, mono-, di-, and tri-chloroanilines has been developed.Normal phase separation by liquid chromatography was performed using a cyano propyl methyl silica column, and atmospheric pressure photoionization was employed as interface with mass spectrometer.The developed method was evaluated in terms of limit of detection, accuracy, and precision. The quantification limit for all the compounds ranged between 7 and 112 ng L⁻¹, while recovery for all the compounds was higher than 94%. The method was tested by analyzing different industrial wastes, showing residual contamination by most of the analytes.     

Raman effect in the x-ray region

This paper presents a brief review of x-ray Raman scattering and some of our calculations on Raman scattered line shapes from light elements. We summarise the history of the Raman process in the x-ray region and present a detailed theory of the Raman scattering from an atomic many-electron system. Actual calculations of the Raman cross-section using this theory in single-particle approximation are given. The process of internal resonance Raman scattering is also discussed in the same formulation. The Raman cross-section is compared with the cross-sections of other x-ray scattering processes.     

Scaling of differential cross-section in high energy proton-helium scattering

Possible occurrence of scaling of differential cross-section for high energy hadronnucleus elastic scattering is demonstrated takingp-⁴He scattering as an example and using three well-known scaling variables proposed earlier for hadron-hadron scattering. The available data on differential cross-section ratio betweenE _lab=45 and 393 GeV are found to scale in all the three variables reasonably well and the positions of the dip and the secondary maximum are found to follow the predicted patterns of behaviour as a function of energy. Extrapolating the fits to the available slope-parameter data onto higher energies and using the scaling curves, the positions of the dip and the secondary maximum and the differential cross-section ratio as a function of |t| are predicted for higher energies.     

The Photoionization of Atomic Hydrogen in an Intense Circularly Polarized Laser Field

We calculate nonperturbatively the irfluence of a strong circularly polarized laser beam on the hydrogen atom energy levels by making use of the time-independent formalism proposed by one of us. The photoionization cross section of the hydrogen atom irradiated by this laser beam and the angular distribution of photoelectrons are also calculated. From the numerical results we clearly see the intensity dependence of the whole photoionization process,including the intensity dependence of the photoelectron energies.     

有机物气相色谱法中光离子化灵敏度的定量结构与性质相关性研究

把Ａｍ拓扑指数与分子连接性指数用于有机化合物气相色谱分析的光离子化灵敏度的结构－性质相关性研究中,并将遗传算法（ＧＡ）引用于本研究中建模,与相应体系的光离子化灵敏度进行相关分析时发现,Ａm指数,分子连接性指数均能较好地反映化合物的结构特征,但各有特点,ＧＡ算法所得结果优于多元回归分析。