Vm. Shabaev et al., RELATIVISTIC RECOIL CORRECTION TO HYDROGEN ENERGY-LEVELS, Journal of physics. B, Atomic molecular and optical physics, 31(8), 1998, pp. 337-339
The relativistic recoil correction to hydrogen energy levels is calcul
ated to all orders in alpha Z for the point nucleus. Previously publis
hed values have been improved in accuracy. It is found that the recoil
correction, beyond the Salpeter one, amounts to -7.16(1) kHz and -0.7
37(3) kHz for the Is and 2s states, respectively. The corresponding co
ntribution to the 2s-2p(1/2) Lamb shift constitutes -1.324(3) kHz.