Shapes of 59Cu nuclei at moderate excitation energies and spin

Continuum γ-ray spectra from the decay of 59Cu formed at excitation energies of 54 and 74 MeV and angular momenta up to 40ħ have been measured and analyzed. The parameters of the giant dipole resonance have been extracted using the statistical model. The giant dipole resonance parameters for the lower excitation energy agree well with published data for spherical 63Cu nuclei. At the higher excitation, the giant dipole resonance strength distribution is not described by a single Lorentzian fit in disagreement with the findings for 63Cu at the same excitation energy. This seems to be correlated with the onset of spin driven deformations as recently evidenced from the shapes of evaporative particle spectra.