The decay of deformed 59Cu nuclei

The light charged particle emission following the fusion of 32S with 27Al at 100–150 MeV bombarding energies in 10 MeV steps has been studied. Energy spectra and angular distributions of p, d, t, and alpha particles as well as light-particle–light-particle coincidences have been measured. The light charged particle data and the published evaporation residue distributions are compared with statistical model calculations. The comparison shows that the statistical model describes well the experimental observables if account is taken of changes in the level density and barrier apparently due to the onset of deformations at high spins. The spectra of α particles emitted from narrow windows of angular momentum with 28ħ≤Jave≤34ħ have been obtained by means of a subtraction procedure and analyzed to extract emission barriers and level density enhancement factors. The deduced barrier lowering with respect to the spherical barrier is somewhat greater than that predicted by assuming rotating liquid drop model (RLDM) shapes. The level density enhancement factor is comparable with that determined in the past for statistically deformed nuclei.