Nuclear recoil effect on the magnetic-dipole decay rates of atomic   levels
  The effect of finite nuclear mass on the magnetic-dipole transition probabilities between fine-structure levels of the same term is investigated. Based on a rigorous QED approach a nonrelativistic formula for the recoil correction to first order in m_e/M is derived. Numerical results for transitions of experimental interest are presented. 
A. V. Volotka, D. A. Glazov, G. Plunien, V. M. Shabaev, and I. I.   Tupitsyn