A new fully quantum-mechanical method used to calculate the collisional broadening coefficients and shift coefficients of Rb D_1 lines perturbed by noble gases He and Ar

In this work, a new full quantum method is proposed to calculate the broadening and shift coefficients of the D_1 line in neutral collision. Based on the variable phase approach and Baranger theory, this method calculates the scattering phase shift instead of scattering matrix elements in order to simplify the calculation. As an illustration, this method is used to calculate the broadening and shift coefficients of the absorption lines of alkali metal atom Rb, as it collides with buffer gas He and Ar, in a temperature range from 150 K to 800 K. With a comparison with other calculations and experiment measurements, the reasonable agreements in all cases demonstrate the validity and simplicity of this method.     

双飞秒激光脉冲诱导击穿光谱增强特性研究

在大气环境中,以钴为样品,通过单脉冲飞秒激光诱导击穿光谱及共轴双飞秒脉冲激光诱导击穿光谱的对比实验,研究了双脉冲激光诱导击穿光谱的谱线增强机制,测量了双脉冲激光诱导击穿光谱随脉冲时间间隔的变化趋势。结果表明,在最优化的脉冲时间间隔条件下,双脉冲激光诱导等离子体光谱获得明显增强。进一步,通过线性Boltzmann法得出了电子温度随脉冲时间间隔的演化,发现了谱线增强因子和电子温度随脉冲时间间隔呈现出相同的演化趋势,并经历两个明显的变化过程,得出了谱线信号强度的增强依赖于电子温度升高的结论。     

Significant discrepancy between the ionization time for parallel and anti-parallel electron emission in sequential double ionization

The ionization time in sequential double ionization with an elliptically polarized laser pulse has been examined theo- retically using a semiclassical method. The significant discrepancy between the ionization time for parallel and anti-parallel electron emission is predicted numerically for the first time. The impact of the carrier envelope phase offset is also studied in this work.     

Dynamics simulation on interaction of intense laser pulses with atomic clusters

Under classical particle dynamics, the interaction process between intense femtosecond laser pulses and icosahedral noble-gas atomic clusters was studied. Our calculated results show that ionization proceeds mainly through tunnel ionization in the combined field from ions, electrons and laser, rather than the electron-impact ionization. With increasing cluster size, the average and maximum kinetic energy of the product ion increases. According to our calculation, the expansion process of the clusters after laser irradiation is dominated by Coulomb explosion and the expansion scale increases with increasing cluster size. The dependence of average kinetic energy and average charge state of the product ions on laser wavelength is also presented and discussed. The dependence of average kinetic energy on the number of atoms inside the cluster was studied and compared with the experimental data. Our results agree with the experimental results reasonably well.     

Peripheral collisions of highly charged ions with metal clusters

Within the framework of the dynamical classical over-barrier model,the soft collisions between slow highly charged ions(SHCIs) Ar 17+ and the large copper clusters under large impact parameters have been studied in this paper.We present the dominant mechanism of the electron transfer between SHCIs and a large metal cluster by computational simulation.The evolution of the occupation of projectile ions,KL x satellite lines,X-ray yields,Auger electron spectrum and scattering angles are provided.     

Half-Lives for Alpha Radioactivity of Elements with 104 ≤ Z ≤ 120 within Unified Fission Model

α decay half-lives are calculated using the Qα values obtained by Semi-empirical Shell Model in the framework of the Unified Fission Model (UFM) with the Coulomb repulsion, nuclear attraction due to proximity potential, and rotational energy due to angular momentum transfer of α particle. In addition, the calculated and experimental half-lives of 425 nuclei are compared to check the validity of the model applied on α decay. The calculated half-lives of α decay are in good agreement with the experimental data. Finally, some usefulpredications on the α decay half-lives are provided for future experiments.     

Images of triple gas electron multiplier with pixel-pads

Testing of a triple gas electron multiplier (GEM) with pixel-pads is described. Images by scanning and suspending radioactive sources were obtained by using 96 channels digital data acquisition (DAQ) system which was composed of 96 8× 8~mm² pads and associated electronics channels.     

^106,110Pd （p,nγ）^106,110 Ag reactions at Ep = 6.0 - 7.7 MeV

This paper reports that the experimental excitation functions of reaction （p,n） are measured for ^106pd and ^110pd at proton energy Ep = 6.1 - 7.5 MeV and Ep = 6.0 - 7.7 MeV respectively. The off-resonance excitation functions were compared with calculation values of the statistical model. A new formula used to estimate the peak cross section of isobaric analogue resonance was tested and it was found that calculation values agree reasonably well with the present data within experimental error, which confirms that the excitation strength of isobaric analogue state in （p,n） reaction not only depends on its spin, but also proportionally increases with the projectile proton spatial transmission Tp and the spectroscopic factor S for reaction （d,p） on the same target.     

低能高电荷态Arq+(q=12,13)离子诱发钼L壳层X射线强度的研究

本文报导了低能高电荷态Arq (q=12,13)离子诱发的钼L壳层X射线强度随入射粒子能量的变化趋势,研究表明当入射粒子能量高于220 keV时,钼L壳层X射线强度有明显增加的的趋势.同时,我们提出了一个简单的模型去估计这种趋势随入射能量的变化.模型计算的结果与实验值符合的比较好.