Microscopic determination of energy surfaces at very high spin states

Deformation energy surfaces for very high angular momentum states in the rare earth nuclei are calculated microscopically for β and γ deformations using a pairing, quadrupole and Coulomb Hamiltonian. The parameters of the Hamiltonian are adjusted to the ground state deformations and the odd-even mass differences. It is found that even with the Nilsson basis one may obtain the correct asymptotic moment of inertia by omitting a few high lying large angular momentum basis states which are depressed too much by the l2 term. Similarities and discrepancies between the proposed microscopic model and the Strutinsky calculations are displayed and discussed. The advantages as well as the limitations of the microscopic description presented here are analysed. (orig.)