Further explorations of the alpha-particle optical model potential at low energies for the mass range A=45-209

TL;DR

This paper refines the alpha-particle optical model potential at low energies for nuclei with mass numbers 45 to 209, based on recent high-precision reaction data, improving predictions for reaction cross sections especially for well-deformed nuclei.

Contribution

The work provides an updated optical model potential with increased surface imaginary potential depth and radius adjustments, enhancing the accuracy of reaction cross section calculations without empirical rescaling.

Findings

Improved agreement with experimental reaction data for A>130.

Enhanced modeling of well-deformed nuclei reactions.

No empirical rescaling needed for gamma/neutron widths.

Abstract

The recent high-precision measurements of alpha-particle induced reaction data below the Coulomb barrier (B) make possible the understanding of limits and possible improvement of a previous optical model potential (OMP) for alpha-particles on nuclei within the mass number range 45<A<209 [M. Avrigeanu et al., Phys. Rev. C 82, 014606 (2010)]. An updated version of this potential is given in the present work concerning mainly an increased surface imaginary potential depth well below B for A>130. Moreover, underestimation of reaction cross sections for well-deformed nuclei is removed by using ~7% larger radius for the surface imaginary part of this spherical OMP. Improved input parameters based on recent independent data, particularly gamma-ray strength functions, but no empirical rescaling factor of the gamma and/or neutron widths have been involved within statistical model calculation of the corresponding (alpha,x) reaction cross sections.