Isotope shifts and zero-point motion of the nuclear surface

A simple procedure for correcting Hartree-Fock mean square radii for the effect of zero-point motion of the nuclear surface is proposed. The procedure has been applied to the calculation of the isotope shifts for even-even nuclei at the onset of deformation in the rare earth region, and a consistent improvement of agreement between the measured and calculated isotope shifts results. Preliminary results about the effect of pairing correlations on the nuclear radius have been also obtained. The effects seem to be significant, comparable with standard isotope shifts, and to depend on the effective two-body force used.