Ground-state configurations of ionic species I through XVI for Z=57-74 and the interpretation of 4d-4f emission resonances in laser-produced plasmas
Ground-state configurations of ionic species I through XVI for Z=57-74 and the interpretation of 4d-4f emission resonances in laser-produced plasmas
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DOI：
10.1103/physreva.25.275
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发表时间：
1982
影响因子：
2.9
通讯作者：
P. K. Carroll;G. O'Sullivan
中科院分区：
文献类型：
--
作者：
P. K. Carroll;G. O'Sullivan
本文给出了从纯金属靶激光等离子体中观察到的从Z=56到Z=60的Ba(Z=56)到Nd(Z=60)元素在70-130？波长范围内的光谱。这就完成了我们对两个光学厚度区域中从铯到氢的元素光谱的调查。这两组光谱显示出显著的差异。为了解释整个结果范围，我们需要知道离子的基态组态，在Z=55−71时，直到XVI的阶段。从现有的有限项分析中，提出了一张合理的地面构型表。在表格的编制过程中，研究了在Z一定的情况下，增加电离对波函数收缩的影响，并推断从Ce到Lu的元素在第六和第七光谱之间，4f电子比5p更紧密地结合在一起；同样，在第14和第15光谱之间，4f电子获得的结合能比5 S的更高。因此，对于相当大范围的离子级，特别是在稀土中，地面组态具有部分填充的4f壳层。此外，在相同的离子能级中，4f、5p和5 S能量保持相对较近的位置，使得5p L 4f n−L的组态非常接近标称基态。4d94fn+1，4d95pL 4fn−L+1，4d94fn+1，4d94fn+1，4d94fn+1，4d95p L 4fn−L+1型的重叠激发组态的相应流形，观测到的共振来自组态的上流形和下流形之间允许的所有4d Femar4f跃迁。计算了跃迁的数量，在大多数情况下是非常大的。因为主量子数不变，所以对于任何一种元素的不同离子阶段，跃迁往往会重叠。共振的宽度和变化的复杂性可以通过现有的理论以令人满意的方式解释，即使是定性的。化合物和金属光谱之间的显著差异可以用活性物种的数密度对两种等离子体的发射和吸收过程的影响来解释。
Spectra of the elements barium (Z= 56) through Nd (Z= 60) observed in laser-produced plasmas from pure-metal targets in the wavelength region 70-130 Å are presented. This completes our survey of the spectra of elements from cesium to hafnium in two regimes of optical thickness. The two sets of spectra show significant differences. In order to interpret the whole range of results, we need to know the ground-state configurations of ions in stages up to XVI for Z= 55− 71. From the limited-term analyses available, a table of plausible ground configurations is proposed. In the preparation of the table, the effect of increasing ionization, for a fixed Z, on wave-function contraction is studied, and it is inferred that the 4 f electron becomes more tightly bound than 5 p between the sixth and seventh spectra of the elements from cerium to lutetium; similarly the 4 f electron attains a higher binding energy than does the 5 s between the fourteenth and fifteenth spectra. Consequently, for a considerable range of ion stages, particularly in the rare earths, the ground configurations have a partially filled 4 f shell. Furthermore, in the same ion stages, the 4 f, 5 p, and 5 s energies stay relatively close together so that configurations of the type 5 p l 4 f n− l lie very near the nominal ground configuration. A corresponding manifold of overlapping excited configurations of the type 4 d 9 4 f n+ 1, 4 d 9 5 p l 4 f n− l+ 1 is also expected and the observed resonances arise from all of the 4 d− 4 f transitions permitted between the upper and lower manifolds of configurations. The numbers of transitions are calculated and in the majority of cases are very great. Because the principal quantum number does not change, the transitions will tend to overlap for different ion stages of any one element. The widths and varying complexity of the resonances can be explained in a satisfactory, if qualitative, way by means of available theory. The very considerable difference between the compound and metal spectra can be explained in terms of the effect of number density of the active species on both emission and absorption processes in the two types of plasma.