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arXiv · 2606.04868

Resolving the Blueshift in Calculations of the EUV Spectrum of Multiply Charged Tin Ions

M. L. Reitsma·J. Sheil·O. O. Versolato·E. V. Kahl·J. C. Berengut
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Abstract

We report ab initio relativistic calculations on the complex open shell Sn$^{12+}$ highly charged ion, a prototypical plasma ion relevant for extreme ultraviolet (EUV) nanolithography. Previous calculations of EUV emissivity in tin plasmas consistently generate a spectrum in which the region of peak emissivity is blueshifted relative to experiment. By optimising our numerical methods to take full advantage of modern, high-performance CPU architectures, we are able to completely saturate the configuration interaction within the $n=4$ shell. Coupled with a thorough treatment of core-valence correlation we resolve the blueshift, finding a surprisingly large influence of highly excited states on the spectrum that is dominated by multiply excited states.

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M. L. Reitsma, J. Sheil, O. O. Versolato, E. V. Kahl, J. C. Berengut. 2026-06-03. Resolving the Blueshift in Calculations of the EUV Spectrum of Multiply Charged Tin Ions. https://arxiv.org/abs/2606.04868

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