A mini-Wigner effect in p-n interactions in heavy nuclei and the 0[110] transformation in the Nilsson scheme

Abstract

We show that delta V-pn values in the rare earth region show peaks, reminiscent of the spikes at N = Z in light nuclei, but occurring at N-val similar to Z(val). These peaks, evident for both even and odd Z values, are interpreted in terms of large spatial overlaps of respective proton and neutron wave functions whose Nilsson quantum numbers are related by delta K[delta N, delta n(z), delta A] = 0[110]. That is, the wave functions differ only by a single oscillator quantum in the z-direction. The implications of this for the development of collectivity and deformation in heavy nuclei, and the locus of this development, are discussed.