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Description
Recent advances in theoretical techniques allow high precision calculations for the high-lying Rydberg P-states of helium up to principal quantum number n = 35 [1]. The present work develops extrapolation techniques based on the Ritz quantum defect method for the nonrelativistic energy, and 1/n expansions for the relativistic and quantum electrodynamic corrections which otherwise violate the Ritz expansion ansatz that only even powers of 1/n contribute. The resulting ionization energies of the P-states are accurate to better than $\pm$1 kHz in the range n > 35. Comparison with experimental transition frequencies up to n = 102 [2] yield ionization energies for the $1s2s\;^3S_1$ state. The results confirm a 9$\sigma$ discrepancy between theory [3] and experiment for the ionization energy of the $1s2s\;^3S_1$ state.
[1] G.W.F. Drake, A.T. Bondy, O.P. Hallett and B.C. Najem, Phys. Rev. A 113, 012810 (2026).
[2] G. Clausen et al. Phys. Rev. A 111, 012817 (2025).
[3] V. Patkos V.A. Yerokhin and K. Pachucki, Phys. Rev. A 103, 042809 (2021).
| Keyword-1 | helium atomic theory |
|---|---|
| Keyword-2 | Rydberg states |
| Keyword-3 | precision tests |