Neutron decay of high excited states of spherical nuclei

The substructures in the photoneutron cross sections of the spherical nuclei are studied experimentally. The data on the structure of the (γ,n) reaction cross sections for 208 Pb and 141 Pr obtained using the bremsstrahlung method are given. The experimental data are compared with the results of calculations with the quasiparticle phonon nuclear model. The results obtained show the possibility of reliable identification of the substructures in the photoabsorption cross sections for nearly magnetic nuclei in the low-energy region. These substructures find a natural explanation from the microscopic point of view as being the result of nonuniform distribution of the electromagnetic strength. This nonuniform distribution is a consequence of individual features of the single-particle and collective degrees of freedom. The substructures in the high-energy region are the results of contributions from different multipole giant resonances. The conclusion is made that experimental and theoretical studies of the neutron decay of the high-lying nuclear states provide the basis for their structure revealing. 19 refs., 1 tab., 2 figs