Excitation energy dependence of the level density for fissionable nuclei

Starting from a realistic set of single-particle levels, a microscopic calculation of nuclear level densities is performed. The washing out of the shells and the blocking of the pairing interaction with increasing excitation energy are shown for ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}$ and ${}_{}{}^{194}{}_{}{}^{}\mathrm{Hg}$ at different deformations. For ${}_{}{}^{210}{}_{}{}^{}\mathrm{Po}$ the variation with the parameters of the nuclear potential is also discussed. Theoretical values at different deformations and excitation energies are compared with the existing experimental information on level density in ${}_{}{}^{194}{}_{}{}^{}\mathrm{Hg}$, ${}_{}{}^{193}{}_{}{}^{}\mathrm{Hg}$, ${}_{}{}^{193}{}_{}{}^{}\mathrm{Au}$, and ${}_{}{}^{190}{}_{}{}^{}\mathrm{Pt}$.