Shell energy and the level-density parameter of hot nuclei
Abstract
Macroscopic-microscopic calculations have been performed with the Yukawa folded mean field for 134 spherical even-even nuclei and 6 deformed ones at temperatures $0\ensuremath{\leqslant}T\ensuremath{\leqslant}5$ MeV and elongations ranging from oblate shapes to the scission configuration of fissioning nuclei. The Strutinsky type free-energy shell corrections for this sample of nuclei and their temperature and deformation dependence are found by a folding procedure in particle-number space. The average dependence of the single-particle level-density parameter on mass number $A$ and isospin $I$ is determined and compared with previous estimates obtained using the relativistic mean-field theory, the Hartree-Fock approximation with the Skyrme effective interaction, and the phenomenological Thomas-Fermi approach adjusted to experimental data. The estimates for the level-density parameter obtained for different deformations are fitted by a liquid-drop type expression.