The role of $\alpha$ clustering in the binary complex fragment decay of fully energy-relaxed composites ${}^{24,25}\mathrm{Mg}^{*}$, formed in ${}^{12,13}\mathrm{C}+{}^{12}\mathrm{C}$ reactions, has been studied. The inclusive isotopic energy distributions of the emitted fragments ${}^{6,7}\mathrm{Li}$ and ${}^{7,8,9}\mathrm{Be}$ have been measured. The ratio of the measured fully dissipative (fissionlike) yields of each isotopic fragment obtained in the two reactions was compared with the corresponding statistical model prediction of the same. Unlike in the case of ${}^{6,7}\mathrm{Li}$ fragments, the measured yield ratios of ${}^{7,8,9}\mathrm{Be}$ fragments were found to deviate substantially from the statistical model predictions of the same. The observed deviations were due to the enhancement in the measured yields of ${}^{7,8,9}\mathrm{Be}$ fragments (with respect to the respective statistical model predictions) only in specific exit channels containing either ${}^{16}\mathrm{O}$ or ${}^{18}\mathrm{O}$, both well known $\alpha$-cluster nuclei, as the complementary binary fragment. The present data indicated, for the first time, the survival and sustained influence of cluster correlations on dissipative binary decay of hot composites ${}^{24,25}\mathrm{Mg}^{*}$ at excitation energy of $\sim 2.25$ MeV/nucleon.

• Received 24 March 2016
• Revised 4 August 2016

DOI:https://doi.org/10.1103/PhysRevC.94.051601