Shell effects in elastic scattering of nucleons by nuclei and neutron strength functions

Translated from Zh. Eksp. Teor. Fiz., Pis'ma Red.; 17: No. The shell approach to the description of nucleon scattering by nuclei is used to parametrize the scattering matrix averaged over the resonances of the compound nucleus. Concrete calculations are performed for the s-neutron strength functions. It is shown that, in contradiction to the predictions of the optical model, the magnitude and the isotopic dependence of the strength function at the minimum (A ~ 100 to 140) are determined, in the main, by the spectroscopic factor of the 3s state. (auth)