Complete and incomplete fusion dynamics of ^6,7Li + ¹⁵⁹Tb reactions near the Coulomb barrier

Abstract.

The complete fusion (CF) and incomplete fusion (ICF) cross-sections are estimated for ^{6, 7}Li + ¹⁵⁹Tb reactions using the energy-dependent Woods-Saxon potential model (EDWSP model) and dynamical cluster-decay model (DCM). The CF data of the ⁶Li + ¹⁵⁹Tb(⁷Li + ¹⁵⁹Tb) reaction at above barrier energies is suppressed with reference to expectations of the EDWSP model by 25% (20%) which is smaller than the reported data by ∼ 9% (6%). This suppression is correlated with the projectile breakup effect. The projectiles ^6,7Li are loosely bound systems, which may break up into charged fragments prior to reaching the fusion barrier and subsequently one of the fragment is captured by the target leading to the suppression of fusion data at above barrier energies. The sum of CF and ICF, which is termed as total fusion cross-section (TF), removes the discrepancies between theoretical predictions and the above barrier complete fusion data and hence is adequately explained via the EDWSP model over a wide range of energy spread across the Coulomb barrier. In addition to fusion, the decay mechanism of ⁶Li + ¹⁵⁹Tb reaction is studied within the framework of the dynamical cluster-decay model (DCM). The breakup of the projectile (⁶Li) in the entrance channel indicates the presence of ICF, which is investigated further using the collective clusterization approach of DCM. The present theoretical analysis suggests that a larger barrier modification is needed to address the fusion data of chosen reactions in the below barrier energy region.