洞态Ar原子K_α和K_β伴线和超伴线的理论计算

Theoretical calculation of K_α and K_β X-ray satellite and hypersatellite structures for hollow argon atoms

基于全相对论多组态Dirac-Fock方法,对L壳层旁观空穴下Ar原子退激衰变辐射K-X射线K_(α1,2)(K→L_(3,2))和K_(β1,3)(K→M_(3,2))的6908条伴线和超伴线跃迁能、跃迁概率进行了系统计算,计算结果与文献已有数据比较具有很好的一致性.通过对(K^(-1)L^(-1),l=0-8)伴线和(K^(-2)L^(-l),l=0-8)超伴线跃迁谱线卷积得了其合成谱,给出了L壳层不同空穴数下K-X射线伴线和超伴线的平均能量和平均跃迁强度.结果表明,退激辐射X射线能量以及能移与L壳层空穴个数呈现明显的线性关系.基于结论,进一步给出了跃迁能移与L壳层空穴个数之间的关系表达式.研究结果可以为解释离子、原子碰撞过程中产生的X射线谱提供重要的理论支持.

A systematical knowledge of the satellite and hypersatellite structures of X-ray transitions is of great interest for various research areas, such as the explanation of the X-ray radiation from universe, plasma diagnostics, extreme ultraviolet（EUV） and X-ray sources and so on. Among these researches, the detailed explanation of the complex structures of X-ray satellites and hypersatellites are crucial for understanding the X-ray emission mechanism and the hollow atom formation mechanism. In this paper, the Kαand KβX-ray satellite and hypersatellite structure are theoretically studied for hollow argon atoms with the relativistic multiconfiguration Dirac-Fock（MCDF） method, which includes the Breit and quantum electro-dynamics（QED） corrections. To check the applicability of the method, the transition energies and rates of the diagram lines for Ar are calculated,. and the results are in agreement with previously published data.Then the MCDF calculations of the transition energies and probabilities of Kα1,2（K → L3,2） and Kβ1,3（K→M3,2） X-ray satellites and hypersatellites, which originate from the argon atoms with additional vacancies in the L shell, are carried out. To obtain the overall profile of the K X-ray spectrum, the diagram lines are integrated with the satellites and hypersatellites on the assumption that the intensity is proportional to the corresponding transition probability and each discrete line has a Gaussian distribution profile with a full width at half maximum（FWHM） value of 20 eV. From the convoluted profile, we can obtain the dependence of the average transition energy and relative transition intensity of the satellites and hypersatellites on the initial hollow configuration. It is found that the transition energy shift increases linearly with the number of spectator vacancies in the L shell increasing. For instance, the energy shift of the Kαsatellite caused by L-shell hole is about 20 eV, and that of the Kβsatellite is 48 eV. While for hypersatellite, the energy shift increases greatly due to the double ionization in the K shell. The energy shift increment of Kαand Kβhypersatellites corresponding to L vacancy are 21 and 52 eV, respectively. Finally, four simple empirical formulae for estimating the energy shifts of the Kα, Kβ X-ray satellites and hypersatellite for Ar atom with any number of L-shells vacancies are deduced by using the least square method. These results are useful in explaining various K X-ray spectra and better understanding the collision process.