Influence of 2p-2h excitations in the41Sc-41Ca Coulomb energy shift

The influence of 2p-2h core excitations on the⁴¹Sc-⁴¹Ca Coulomb energy difference is studied. A simple parametrization of the main wave function components shows that the calculated energy shift could only agree with experiment for rather unrealistic values of the amplitudes. Using an effective interaction appropriate for this region, we find that when this kind of excitations is included, the calculated Coulomb energy shift is increased by 105keV.