Continuum γ-ray spectra from the decay of ${}_{}{}^{59}{}_{}{}^{}\mathrm{Cu}$ 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 ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$ 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 ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$ 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.

• Received 7 March 1989

DOI:https://doi.org/10.1103/PhysRevC.40.R1570