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QED calculation of the n=1 and n=2 energy levels in He-like ions

A. N. Artemyev·V. M. Shabaev·V. A. Yerokhin·G. Plunien·G. Soff
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Abstract

We perform ab initio QED calculations of energy levels for the $n=1$ and $n=2$ states of He-like ions with the nuclear charge in the range $Z = 12$-100. The complete set of two-electron QED corrections is evaluated to all orders in the parameter $\aZ$. Uncalculated contributions to energy levels come through orders $α^3 (\aZ)^2$, $α^2 (\aZ)^7$, and higher. The calculation presented is the first treatment for excited states of He-like ions complete through order $α^2 (\aZ)^4$. A significant improvement in accuracy of theoretical predictions is achieved, especially in the high-$Z$ region.

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A. N. Artemyev, V. M. Shabaev, V. A. Yerokhin, G. Plunien, G. Soff. 2005-01-15. QED calculation of the n=1 and n=2 energy levels in He-like ions. https://doi.org/10.1103/physreva.71.062104

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