The main properties of γ-decay cascades in heavy nuclei and the possibility of their determination

The properties of high-lying states in some heavy nuclei in the mass region 114 ≤ A ≤ 196 are discussed. The experimental data on nuclear level densities at excitation energies above 2 MeV, the peculiarities of the structure of the intermediate levels of two-step cascades, the distribution of level spacing between the most intense cascades, the dependence of average intensities on the energy of the primary transitions and the experimental possibilities to observe phase transitions and their influence on γ-decay modes are presented and analyzed in detail. The experimental data are compared with those predicted using different theoretical models. 18 refs., 1 tab., 6 figs