Relaxation effect and radiative corrections in many-electron atoms
  We illuminate the importance of a self-consistent many-body treatment in calculations of vacuum polarization corrections to the energies of atomic orbitals in many-electron atoms. Including vacuum polarization in the atomic Hamiltonian causes a substantial re-adjustment (relaxation) of the electrostatic self-consistent field. The induced change in the electrostatic energies is substantial for states with the orbital angular momentum $l &;gt; 0$. For such orbitals, the relaxation mechanism determines the sign and even the order of magnitude of the total vacuum polarization correction. This relaxation mechanism is illustrated with numerical results for the Cs atom. 
Andrei Derevianko, Boris Ravaine, W. R. Johnson