Fission fragment mass and total kinetic energy (TKE) distributions reported in [E. Vardaci et al., Phys. Rev. C 92, 034610 (2015)] for the reaction ${}^{32}\mathrm{S}{+}^{100}\mathrm{Mo}$ leading to ${}^{132}\mathrm{Ce}$ compound nucleus at the excitation energy $E_x=122\mathrm{MeV}$ are analyzed by means of an improved scission-point model that describes the shape of the compound nucleus at scission in terms of Cassini ovals. This study is motivated by a former comparison of the experimental fission data with the predictions of a dynamical model of fission, based on three-dimensional Langevin equations, that showed a significant disagreement with the measured TKE distribution. A broader set of nuclear shapes is accessible with Cassini ovals, in contrast to the more limited flexibility of the “Funny Hills” parametrization used in the dynamical code. For this reason, the present results show a clearer improvement in reproducing the experimental mass and TKE distributions compared to the dynamical model. Moreover, the present work highlights the need to consistently account for a nonequilibrium contribution, such as a deep-inelastic process, in both the mass and TKE distributions, for an estimated amount of $23.5\%$ of the total yield. In the present work, the potential energy surface at the moment of neck rupture (corresponding to the scission parameter $\alpha$ = 0.985) is computed as a function of the shape parameters ${\alpha }_1$, accounting for the mass asymmetry, and ${\alpha }_4$, accounting for the elongation at the scission point. Then a minimization on ${\alpha }_6$, which accounts for small oscillations around the nuclear shape, is performed at each point (${\alpha }_1, {\alpha }_4$). Furthermore, model calculations have been extended beyond the measured fragment mass asymmetry range to investigate the path towards the Businaro-Gallone transition.

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• Fission
• Heavy-ion reaction mechanisms
• Low & intermediate energy heavy-ion reactions
• Nuclear reactions
• Scission point
• 90 ≤ A ≤ 149
• Nuclear structure & decays
• Radiation detectors