α-particle nuclear surface absorption below the Coulomb barrier in heavy nuclei

An analysis of all available α-particle-induced reaction cross sections on nuclei within the mass number range 121≤A≤197, below the Coulomb barrier, is carried out. This analysis leads to an optical potential that describes the α-particle elastic scattering at low energies as well and both elastic-scattering and reaction data for 45≤A≤124. The energy dependence of the surface imaginary potential depth is proved to be essential for understanding α-particle interaction behavior below the Coulomb barrier.