Precise and Accurate Calculations of Electronic Transitions in Heavy Atomic Ions Relevant to Extreme Ultra-Violet Light Sources
F.Koike, K.Nishihara1), A.Sasaki2), T.Kagawa3), T.Nishikawa4), K.Fujima5), T.Kawamura6), and H. Furukawa7)
Phys. Lab. School of Medicine, Kitasato University, Sagamihara 228-8555 Japan
Recently, the 13 nm range extreme ultra-violet emissions of many electron atomic ions are of interest in relation to the semiconductor technologies. We theoretically studied the intra M shell (n=4 shell) transitions of Sn and Xe atomic ions. In this type of the ions, especially of the Sn ions, a peculiar behaviour in the emission spectra has been pointed out by O’Sullivan and Faukner[1]; they discussed the narrowing of 4f-4d spectra as due to the configuration interactions. To gain a further insight of the effects, we carried out a sophisticated calculation using GRASP92[2] and its earlier versions. We found in Sn 12+ ions, for example, that the positions of main peaks of all the n=4 orbitals fall in almost the same radial distances, which enhances the configuration interactions in the M shell. And these configuration interactions cosiderably modify the geometory of the excited electronic states and induce the so called spectral narrowing.
References
[1]G. O’Sullivan, and R. Faukner, Opt. Eng. 33, 3978 (1994)
[2] F. A. Parpia, C. F. Fischer, and I. P. Grant, Commpt. Phys. Commun. 94, 249(1996)
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