FLOW PATTERNS FOR COLLECTIVE ROTATIONS IN HEAVY-NUCLEI

Current and velocity fields for collective rotations are calculated from cranked BCS correlated wave functions for even-even rare earth nuclei. The single-particle Hamiltonian used is that of the Nilsson model. The velocity fields obtained do not yield a spherical inert core, in contrast to the two-fluid model. It is shown that the flow pattern can be represented quite accurately by a superposition of irrotational and rigid flow. The strength of the former can reach up to 60 % - depending on the specific nucleus - in the case without pairing and is usually about 80 % with pairing. Finally several forms for the collective rotational energy are compared. It is found that the classical expression grossly underestimates the correct energies. © 1979.