Effect of clustering on the emission of light charged particles

Abstract

Energy spectra of light charged particles emitted in the reaction $p + {}^{27}\mathrm{Al} \rightarrow {}^{28}\mathrm{Si}^{\ast}$ have been studied and compared with statistical model calculation. Unlike 16O + 12C where a large deformation was observed in 28Si*, the energy spectra of $\alpha$ -particles were well explained by the statistical model calculation with standard “deformability parameters” obtained using the rotating liquid drop model. It seems that the $\alpha$ -clustering in the entrance channel causes extra deformation in 28Si* in the case of 16O + 12C, but the reanalysis of other published data shows that there are several cases where extra deformation was observed for composites produced via non- $\alpha$ -cluster entrance channels also. An empirical relation was found between mass-asymmetry in the entrance channel and deformation, which indicates that along with $\alpha$ -clustering, mass-asymmetry may also affect the emission of a light charged particle.