No abstract

No 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 + Ca Ti 40 20 46,48,50 22 Keywords: depth and diffuseness of Woods-Saxon potential, coupled channel equations, heavyion sub-barrier fusion reactions, diffuseness anomaly

This paper is mainly focused on the limitations of energy independent Woods–Saxon potential and the applicability of energy dependent Woods–Saxon potential (EDWSP) model in conjunction with one-dimensional Wong formula for description of the heavy-ion fusion reactions. The effects of neutron transfer channels and inelastic surface vibrations of colliding nuclei in the enhancement of sub-barrier fusion excitation function data, in the various heavy-ion fusion reactions, have been investigated within the framework of energy independent one-dimensional barrier penetration model, the EDWSP model and the coupled channel code CCFULL. In certain projectile-target combinations, the influences of multi-neutrons transfer between reactants are found to be dominating over the coupling to low lying surface vibrational states. Furthermore, the effects of these dominant degrees of freedom can be simulated by introducing the energy dependence in real part of nucleus–nucleus potential.

The fusion dynamics of [Formula: see text] reaction has been studied using different theoretical approaches like energy-dependent Woods–Saxon potential (EDWSP) model, coupled channel formulation and Wong approach. At sub-barrier energies, the anomalously large enhancement of the fusion cross-section signifies the importance of barrier modification effects for the adequate addressal of experimental data. The EDWSP model, wherein barrier modification effects are introduced via the energy-dependent diffuseness parameter, is used to examine the sub-barrier fusion anomalies. In the framework of coupled channel model, the impacts of collective excitations and/or static deformations of colliding partners are incorporated in the fusion dynamics. In Wong formula, the role of different Skyrme forces such as SIII, KDE0v1, SkT1, SSk, GSkI is analyzed to address the observed fusion enhancement around the Coulomb barrier. Among these, GSkI and SSk forces seem more appropriate for the addressal of fusion dynamics at sub-barrier energies while SIII, SkT1 and KDE0v1 forces give relatively better results at the above barrier region. The SSk (GSkI) force at higher energies overestimate the experimental data and hence treated with the [Formula: see text]-summed Wong approach. The effect of deformations and optimum orientations is duly incorporated in the calculation and hence gives better description to the observed data. In addition, the fusion cross-sections are predicted over extreme energies using EDWSP and [Formula: see text]-summed Wong approach. It is worth mentioning here that the different theoretical approaches (EDWSP, coupled channel and Wong) induce similar kinds of barrier lowering effects, henceforth, they reasonably describe the sub-barrier fusion data of [Formula: see text] reaction.