Gross shell structure at high spin in heavy nuclei

Experimental nuclear moments of inertia at high spins along the yrast line have been determined for a large number of nuclei. They are found to systematically differ from the rigid-body values. The difference is attributed to shell effects which are well described by a rotating Woods-Saxon potential. The data and quantal calculations are interpreted by means of the semiclassical periodic orbit theory. From this new perspective, features in the moments of inertia as a function of neutron number and spin as well as their relation to the shell energies can be understood. Gross shell effects persist up to the highest angular momenta observed.