Fine structure of helium and light helium-like ions

TL;DR

This paper presents detailed calculations of the fine-structure splitting in helium and light helium-like ions, achieving high accuracy and confirming theoretical predictions with experimental data, and uses this to determine the fine-structure constant precisely.

Contribution

The paper provides new high-precision calculations of fine-structure splittings in helium-like ions and uses these results to accurately determine the fine-structure constant.

Findings

Theoretical results agree with experimental data for helium and light helium-like ions.

The fine-structure constant is determined with an accuracy of 31 parts per billion.

Calculations extend up to nuclear charge Z=10.

Abstract

Calculational results are presented for the fine-structure splitting of the 2^3P state of helium and helium-like ions with the nuclear charge Z up to 10. Theoretical predictions are in agreement with the latest experimental results for the helium fine-structure intervals as well as with the most of the experimental data available for light helium-like ions. Comparing the theoretical value of the 2^3P_0-2^3P_1 interval in helium with the experimental result [T. Zelevinsky et al. Phys. Rev. Lett. 95, 203001 (2005)], we determine the value of the fine-structure constant \alpha with an accuracy of 31 parts per billion.