A joint analysis of the elastic-scattering angular distributions and fusion cross sections together with the $S$ factor for the ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ system near and below the Coulomb barrier is reported. To describe these observables within the framework of the optical model, a comparative study of microscopic $\alpha$-$\alpha$ double-folding clusters and phenomenological shallow potentials with surface-transparent imaginary parts is performed. Although the phenomenological Woods-Saxon type of shallow real potentials is unable to provide a consistent explanation of these data, the $\alpha$-$\alpha$ double-folding cluster potential obtained by considering the $\alpha$-cluster structure of ${}^{16}\mathrm{O}$ provides a considerable improvement. The $\alpha$-$\alpha$ double-folding cluster potential also reproduces the normalized resonant energy states of ${}^{32}\mathrm{S}$ for the $N=24$ cluster band.

• Received 11 November 2009

DOI:https://doi.org/10.1103/PhysRevC.81.024615