title: Charge radius isotope shift across the N=126 shell gap.
abstract: We revisit the problem of the kink in the charge radius shift of neutron-rich even isotopes near the N=126 shell closure. We show that the ability of a Skyrme force to reproduce the isotope shift is determined by the occupation of the neutron 1i(11/2) orbital beyond N=126 and the corresponding change it causes to deeply-bound protons orbitals with a principal quantum number of 1. Given the observed position of the single-particle energies, one must either ensure occupation is allowed through correlations, or not demand that the single-particle energies agree with experimental values at the mean-field level.
authors: Department of Physics, University of Surrey, Guildford, United Kingdom.
authors: P M
authors: PM
authors: Goddard
authors: P D
authors: PD
authors: Stevenson
authors: A
authors: A
authors: Rios