Va. Yerokhin et Vm. Shabaev, One-loop self-energy correction to the 1s and 2s hyperfine splitting in H-like systems - art. no. 012506, PHYS REV A, 6401(1), 2001, pp. 2506
The one-loop self-energy correction to the hyperfine splitting of the 1s an
d 2s levels in H-like low-Z atoms is evaluated to all orders in Z alpha. Th
e results are compared to perturbative calculations. The residual higher-or
der contribution is evaluated. Implications to the specific difference of t
he hyperfine-structure intervals 8 Delta nu (2)-Delta nu (1) in He+ are inv
estigated.