Confirmation and extension of a mini-valence Wigner-like energy in Sm, Gd, and Dy

An earlier study revealed an unexpected enhancement in valence proton-neutron interaction strengths in certain heavy deformed even-even nuclei with equal numbers of valence protons and valence neutrons. The paper reports on an extension of those results to the entire span of deformed nuclei from Sm to W using mass data taken in the interim.