ON THE ANGULAR-MOMENTUM DEPENDENCE OF NUCLEAR-LEVEL DENSITIES

Angular-momentum dependence of nuclear-level densities at finite tempe ratures are investigated in the static-path approximation (SPA) to the partition function using a cranked quadrupole-interaction hamiltonian in the following three schemes: (i) cranking about the x-axis, (ii) c ranking about the z-axis and (iii) cranking about the z-axis but corre cting for the orientation fluctuation of the axis. Performing numerica l computations for an sd- and a pf-shell nucleus, we find that the x-a xis-cranking results are satisfactory for reasonably heavy nuclei and this offers a computationally faster method to include the angular-mom entum dependence at high temperatures in the SPA approach. It also app ears that at high spins the inclusion of the orientation-fluctuation c orrection would be important.