等离子体屏蔽效应对类氢离子能级结构和辐射跃迁性质的影响

Influence of plasma effect on the energy levels and transition probabilities of hydrogen-like ions

在Debye-Hckel屏蔽近似下,基于相对论Dirac-Fock方法,发展了包括等离子体屏蔽效应的自洽场计算程序.使用该程序研究了等离子体屏蔽效应对类氢离子能级结构和辐射跃迁性质的影响.结果表明,当原子处于等离子体环境中,所有束缚态能级向连续态移动,移动量随着屏蔽长度的减小而增大.振子强度随屏蔽长度的变化也表现出了相同的规律.进一步分析了相对论效应和等离子体屏蔽效应的耦合,发现对于中Z元素,相对论效应和等离子体屏蔽效应存在较强的耦合.讨论了等离子体屏蔽效应对原子精细结构能级的影响.计算发现,由于等离子体屏蔽效应,原子的能级次序发生了变化,κ简并被消除.

The effect of plasma screening has been investigated by incorporating the Debye potential into the framework of the relativistic Dirac-Fock method, and the GRASP92 code has been modified to perform the calculations. As an example, we have studied the plasma effecting on energy levels and transition probabilities of H-like ions embedded in dense and hot plasma. The following three important results have been obtained： （1） all energy levels are shifted away from their unscreened values toward the continuum, and the shift of energy increases as screening strength decreasing. Furthermore, for each eigenstate with given quantum numbers n and l, there is a finite value of ~tc （critical length） which corresponds a zero energy. （2） For a given transition, the oscillator strength and transition probability decrease with increase of the screening strength. （3） The degenerate fine-structure levels with the same n, j but different l can be destroyed by the plasma screening effect, even without the consideration of the Lamb shift, which has received little attention in the past.