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
(1)Institute of Laser Engineering, Osaka University, Osaka 565-0871, Japan
(2)Advanced Photon Research Center, JAERI, Kyoto 619-0215 Japan
(3)Faculty of Science, Nara Women’s University, Nara 630-8506, Japan
(4)Faculty of Engineering, Okayama University, Okayama 700-8530, Japan
(5)Faculty of Engineering, Yamanashi University, Kofu, 400-8510, Japan
(6)Tokyo Institute of Technology, Yokohama 226-8502 Japan
(7)Institute for Laser Technology, Osaka, 550-0004, 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)