Heavy-ion optical potentials from few-nucleon transfer reactions

Abstract

The sensitivity of forward angle heavy-ion transfer calculations to the details of the imaginary optical potential in the region of the nuclear surface is demonstrated. A phenomenological imaginary potential, consisting of a deep volume term of sharp diffusivity and a shallow surface term of standard diffusivity, is proposed and used in distorted-wave Born-approximation calculations to reproduce a variety of angular distribution shapes. The proposed parametrization of the imaginary potential allows the region of the nuclear surface to be transparent enough to produce large forward angle cross sections, seen experimentally, and yet remain strongly enough absorbing in the nuclear interior to suppress unphysical contributions from this region. Bound state configuration dependence of angular shapes, produced in two-particle transfer calculations with weakly absorbing volume potentials, is shown to be removed by the use of the proposed surface transparent potentials.