Calculation of cross sections for neutron capture by nuclei formed in astrophysical r processes

On the basis of statistical models, the cross sections for neutron capture by heavy nuclei have been calculated at low energies. The effect of the spin dependence of the level density on the cross sections sigma(n gamma) has been considered. The results of these calculations are shown to be in satisfactory agreement with experimental data. The approach developed on the basis of statistical models has been used to predict the cross sections for neutron photoabsorption by unstable neutron-excess nuclei at low energies (from 10 to 100 keV) peculiar to astrophysical nucleosynthesis in r processes.