Quasielastic scattering excitation function at large backward angle has been measured for the weakly bound system ${}^7\mathrm{Li}+{}^{159}\mathrm{Tb}$ at energies around the Coulomb barrier. The corresponding quasielastic barrier distribution has been derived from the excitation function, both including and excluding the $\alpha$ particles produced in the reaction. The centroid of the barrier distribution obtained after inclusion of $\alpha$ particles was found to be shifted higher in energy, compared with the distribution excluding the $\alpha$ particles. The quasielastic data, excluding the $\alpha$ particles, have been analyzed in the framework of continuum discretized coupled-channels calculations. The quasielastic barrier distribution for ${}^7\mathrm{Li}+{}^{159}\mathrm{Tb}$, has also been compared with the fusion barrier distribution for the system.

• Received 20 August 2020
• Revised 8 October 2020
• Accepted 7 December 2020

DOI:https://doi.org/10.1103/PhysRevC.103.014606