Systematic failure of static nucleus–nucleus potential to explore sub-barrier fusion dynamics

Abstract

This paper addresses the validity of the static Woods–Saxon potential and the energy dependent Woods-Saxon potential (EDWSP) for description of sub-barrier fusion dynamics. The low lying surface vibrations of colliding nuclei and neutron transfer channels are found to be major factors responsible for fusion enhancement at sub-barrier energies. Theoretical calculations based upon the static Woods–Saxon potential obtained using the one-dimensional Wong formula fail to explain the energy dependence of the sub-barrier fusion cross-section of systems. The role of inelastic surface vibrations is properly entertained within the context of coupled channel calculations performed using the CCFULL code. However, the EDWSP model, in conjunction with the one-dimensional Wong formula, accurately explains the sub-barrier fusion enhancement of systems and simulates the influence of nuclear structure degrees of freedom, such as the inelastic surface vibrational states of colliding pairs. In EDWSP model calculations, a wide range of diffuseness parameters, ranging from to which is much larger than a value extracted from the elastic scattering data, is required to bring the observed fusion enhancement.