Effect of the inelastic couplings on the scattering of alpha particles by ¹²C at low energies

Abstract

We study the effects of the coupling to the first 2 + 12 C excited state on the elastic scattering and capture reaction for the α + 12 C system. The flux absorption from the elastic channel to the capture reaction is simulated by a tiny imaginary part included in the optical potential. Our analyses show that the effect of the coupling is quite significant even at energies below the threshold of the inelastic channel. We also study the behavior of the polarization potential as a function of the energy and angular momentum.

Reinterpreting the energy dependence of the optical potential

“…To our knowledge, this is the first time that such kind of calculations are reported. As already commented, the bare interaction (real and imaginary parts of the nuclear potential) assumed in the present work for α + 208 Pb has provided a quite good description of the fusion, elastic and inelastic scattering processes at sub-barrier energies for many α-nucleus systems [8][9][10]. In the CC calculations performed in the present work, we adopted the values of the coupling parameters within a rather schematic and arbitrary form, with the purpose of simulating myriad of states with high excitation energies.…”

“…In earlier works [8][9][10], we proposed a theoretical model for the nuclear potential of α-nucleus systems, which is energy independent and has no adjustable parameters. This interaction has been successfully applied in the description of fusion, elastic and inelastic scattering data for many systems at low energy regions [8][9][10]. In the present work, we assume the same interaction as the bare potential to study the elastic scattering for α + 208 Pb in a wide energy range.…”

Folding-type coupling potentials in the context of the generalized rotation–vibration model

“…In [14], we proposed an effective nuclear interaction, u(r) of (9), to describe the lowenergy α + α scattering. The same interaction was successful in describing the elastic, inelastic and fusion processes for several α-nucleus systems in low energies [13,15]. Thus, we have also assumed this interaction in the present CC calculations:…”

Role of inelastic couplings in 4He + 208Pb elastic scattering in a wide energy range

“…We adopt a parameter-free model for the real part of the OP: the recently proposed Brazilian nuclear potential (BNP) [8]. The effective interaction assumed in the context of the BNP was firmly based on data analyses for alpha-nucleus systems [5,9,10] and, therefore, we consider the BNP an appropriated choice for the nuclear interaction in the present study. In the corresponding REGINA code [8], we assumed the option of 'experimental' charge and matter densities for 4 He and theoretical Dirac-Hartree-Bogoliubov (DHB) distributions for 208 Pb.…”