Abstract
We have derived the complete formula for the contribution to energy levels of an arbitrary triplet state of the helium atom, performed numerical calculations for the and states, and thus improved the theoretical accuracy of ionization energies of these states by more than an order of magnitude. Using the nuclear charge radius extracted from the muonic helium Lamb shift, we obtain the theoretical prediction in excellent agreement with the measured transition energy [X. Zheng et al., Phys. Rev. Lett. 119, 263002 (2017)]. At the same time, we observe significant discrepancies with experiments for the and transitions.
- Received 1 March 2021
- Accepted 22 March 2021
DOI:https://doi.org/10.1103/PhysRevA.103.042809
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