Quadrupole and Hexadecapole Correlations in Rotating Nuclei Studied   within the Single-j Shell Model
  The influence of quadrupole and hexadecapole residual interactions on rotational bands is investigated in a single-j shell model. An exact shell-model diagonalization of quadrupole-plus-hexadecapole interaction can sometimes produce a staggering of energy levels in the yrast bands. 
P. Magierski, K. Burzynski, E. Perlinska, J. Dobaczewski, W.   Nazarewicz