Accurate evaluations of the field shift and lowest-order QED correction   for the ground $1^1S-$states of some light two-electron ions
  Mass-dependent and field shift components of the isotopic shift are determined to high accuracy for the ground $1^1S-$states of some light two-electron Li$^{+}$, Be$^{2+}$, B$^{3+}$ and C$^{4+}$ ions. To determine the field components of these isotopic shifts we apply the Racah-Rosental-Breit formula. We also determine the lowest order QED corrections to the isotopic shifts for each of these two-electron ions. 
Alexei M. Frolov
physics.atom-ph