Light-charged-particle evaporation from hot 31P nucleus at E*∼ 60 MeV

The inclusive energy spectra of light charged particles, such as, α, p, d and t, evaporated from the hot 31P nucleus at an excitation energy E*∼ 60 MeV, have been measured at various angles. The compound nucleus 31P has been populated using two different entrance channel configurations; i.e., 7Li (47 MeV) + 24Mg and 19F (96 MeV) + 12C reactions, leading to the same excitation energy of the compound system. It has been observed that the spectra obtained in the 7Li (47 MeV) + 24Mg reaction follow the standard statistical-model prediction with a spherical configuration of the compound nucleus. But, the spectra obtained in the 19F (96 MeV) + 12C reaction deviate from similar predictions of the statistical model both on higher- as well as on lower-energy sides. Considerable deformation was required to be incorporated in the calculation in order to reproduce the measured-energy spectra in this case. Dynamical trajectory model calculations were not found to play any significant role in explaining the differences in behaviour between the two cases under study. The observed discrepancy has been attributed to the difference in the angular-momentum distributions of the compound nuclei formed in the two reactions.