Microscopic approach to the alpha-particle-nucleus optical potential.

Abstract

A microscopic model for the alpha-particle-nucleus optical potential is presented and applied to \ensuremath{\alpha}${\mathrm{\ensuremath{-}}}^{40}$Ca scattering. Starting with the M3Y force as the basic nucleon-nucleon interaction, the single-channel contribution to the optical potential is calculated by means of the fish-bone model which treats the antisymmetrization between the projectile and the target nucleus in an approximate way. The applicability of the fish-bone model to the \ensuremath{\alpha}${\mathrm{\ensuremath{-}}}^{40}$Ca system is tested by comparison of resonating group calculations with fish-bone model calculations. The potential terms arising from the coupling of the elastic channel to other reaction channels have been calculated in the framework of the nuclear structure approach using random-phase approximation transition densities for intermediate excited states. The elastic scattering cross sections calculated from the microscopic potentials reproduce gross structures of the experimental data. However, the model cannot account for the whole absorption.