Density-dependent photoabsorption cross sections of atomic Xe

The evolution of the photoabsorption cross sections of atomic xenon with number densities varying from ideal gas to condensed matter has been studied by an alternative view in the present work. The alternative expressions of the photoabsorption cross sections presented by Sun et al recently were used with the local field models that has proven to be generalized easily to multiatomic systems including molecules and condensed phase systems. The present results show that the variation of the photoabsorption cross sections of atomic xenon in the giant resonance region from the isolated to the condensed conditions is very small, which agrees well with the variation law of the solid and gas experiments.     

Imprints of molecular orbitals using photoelectron angular distribution by strong laser pulses of circular polarization

We theoretically investigate the strong-field ionization of H+2 molecules in four different electronic states by calculating photoelectron angular distributions in circularly polarized fields. We find that the structure of photoelectron angular distribution depends on the molecular orbital as well as the energy of the photoelectron. The location of main lobes changes with the symmetric property of the molecular orbital. Generally, for molecules with bonding electronic states, the photoelectron's angular distribution shows a rotation of π/2 with respect to the molecular axis, while for molecules with antibonding electronic states, no rotation occurs. We use an interference scenario to interpret these phenomena. We also find that, due to the interference effect, a new pair of jets appears in the waist of the main lobes, and the main lobes or jets of the photoelectron's angular distribution are split into two parts if the photoelectron energy is sufficiently high.     

Relation between delayed luminescence and functional state in soya seeds

Summary The possibility of using the parameters connected to delayed luminescence to detect thermal stress conditions in soya seeds is discussed here and the results of the measurement of photoinduced emission conducted on soya seeds characterized by a different vegetative vigour are presented. A phenomenological relationship between the total re-emission and the growth velocity was found. The distributions of the decay times relative to the different conditions of stress on the seeds have given indications towards the existence of different dynamics. On the basis of the results it seems that a correlation exists between the functional state of the seeds and delayed luminescence. The authors of this paper have agreed to not receive the proofs for correction.     

苯的同步辐射光电离效率谱的研究

用合肥国家同步辐射实验室光化学站的实验装置研究了苯分子的光电离质谱，从所得光电离效率谱精确地定出了苯分子的电离势及苯离子的出现热，并首次报道了三个苯离子的离解能。     

四氯乙烯的同步辐射光电离研究

利用VUV同步辐射光源和反射式飞行时间质谱仪，在超声冷却条件下对四氯乙烯(C₂Cl₄)进行了光电离研究，通过测量各离子的光电离效率(PIE)曲线，得到了C₂Cl₄的电离势IP(C₂Cl₄) =(9.36±0.05)eV及C₂Cl₄光解离碎片离子C₂Cl₃⁺，C_{关键词： 真空紫外光电离 离子出现势 电离势 四氯乙烯}     

Dynamic behavior of highly excited molecular states in the strong monochromatic laser fields

The dynamic behavior of highly excited molecular states in an external monochromatic field has been investigated in order to establish the general trends in the Rydberg state manifestations in collisional and radiative processes. The effects of interference between direct (background) and resonant interactions and coupling between the continua on the fine structure of collision cross sections and near-threshold photoabsorption spectra are discussed. Analytical expressions for the widths and intensities of the Rydberg lines induced by mixing the field with other quasistationary states are derived and their dependence on the external field strength and frequency are analyzed. It was found that the appreciable stabilization of isolated Rydberg levels observed previously in superstrong fields is also possible in fields much weaker than atomic fields. The possibility of laser control for the energy averaged cross sections and reaction rate constants are considered. All effects are illustrated for thee ^– + H₂ ⁺ system.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 367–386, March, 1994.This work was supported by the Russian Foundation for Basic ReSearch (Grant No. 93-03-4700).     

CH3I同步辐射光电离及生成焓、键能和质子亲合势的测定

在超声射流冷却条件下用VUV同步辐射研究了CH3I分子的光电离过程。测定了CH3I光电离及解离电离产生的CH3I^+, CH3^+和I^+的出现势, 结合已确认的热力学数据, 估算出体系中有关离子的标准生成焓、分子和分子离子的键能、自由基的质子亲合势及母体离子的解离能等数据。对CH3I分子VUV光解离电离通道进行了分析。     

新拓扑指数A_m在有机物气相色谱法中光离子化灵敏度的分析中的应用

本文把Am拓扑指数与分子连接性指数首次用于有机化合物气相色谱分析的光离子化灵敏度的结构-性能相关性研究中，在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，将二者组合，得到了更为满意的构效关系的数学模型。     

New results on the dissociative photoionization of CF(4) and CCl(4)

Using the VIPCO technique, we remeasured and completed the breakdown diagram of CCl(4) (+) up to 21 eV energy. The angle-resolved data show both orientation and alignment of photoelectrons relative to CX(3) (+) fragments from photoionization to the low-lying states of CF(4) (+) and CCl(4) (+). The strength of the orientation (forward/backward asymmetry) is surprising in view of the nearly spherical symmetry of the parent molecules, and calls for theoretical explanation. It may indicate that nuclear and electron motion take place on similar time-scales.     

ASYMMETRY PARAMETERS AND DIFFERENTIAL CROSSSECTIONS FOR PHOTOIONIZATION-EXCITATION OF HELIUM

Asymmetry parameterβ2 for photoionization of helium leaving the He+ ion in the n = 2 level and differential cross sections(DCSs) in the n = 2, 3, 4 levels with photon emission angle θ=90°are provided at photon energies 69－76.8 eV employing the R-matrix method with a 20-term target representation, in which five polarization orbitals 6l are included. The asymmetry parameter β2 and the DCS, in the n=2 level in the region of 69－73eV, are in good agreement with available experimental and theoretical results. Above the n = 3 threshold, we present new theoretical results along with measurements. No theoretical and experimental results can be used to compare with the present calculations of the DCSs for photoionization into the He+ ion in the n = 3, 4 levels.