On the angular momentum dependence of nuclear level densities

Abstract

Angular momentum dependence of nuclear level densities at finite temperatures 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 x-axis, (ii) cranking about z-axis and (iii) cranking about z-axis but correcting for the orientation fluctuation of the axis. Performing numerical computations for an $sd$ and a $pf$ shell nucleus, we find that the x-axis cranking results are satisfactory for reasonably heavy nuclei and this offers a computationally faster method to include the angular momentum dependence at high temperatures in the SPA approach. It also appears that at high spins inclusion of orientation fluctuation correction would be important.