Non-monotonic potential description of α+209Bi elastic scattering

The present work reports the analyses of the experimental angular distributions of α+209Bi elastic scattering at Eα=19−104 MeV using the non-monotonic (NM) potential in the framework of optical model (OM). The NM potential is a complex shallow potential with a soft repulsive core in its real part which has its root in the energy-density functional theory of Brueckner et al. (1968) [28]. The data are analyzed using the real NM potentials of unshifted Gaussian repulsive core with D1=0 (Set-1) and shifted repulsive core with D1≠0 (Set-2) in conjunction with the empirically adjusted imaginary potentials. For both sets, the volume integral per nucleon pair, JR/(4A) for the real potential decreases in magnitude with the incident energy for the energy range considered in this study. The χ2 values and almost similar quality of fits to the experimental data using both the potential sets show that the scattering of α-particles from the 209Bi target is dominated by the potential in the surface region, and the scattering is insensitive to the potential in the central region of the 209Bi nucleus.