Damping of the giant dipole resonance in hot, strongly rotating nuclei

The isovector dipole density-density response of hot rotating nuclei is calculated applying a cranked deformed Nilsson potential together with a separable dipole-dipole residual interaction. The transformation of the response function from the internal rotating coordinate frame to the laboratory frame is discussed and illustrated by classical results for charged particle moving in a harmonic-oscillator potential. Calculations for 108Sn, 152Dy and 196Pb are presented. For 108Sn at high excitation energy thermal fluctuations of the shape gives rise to a rather structureless strength function with a considerable width. For 152Dy and 196Pb superformed minimal of the potential surface are predicted. The coupling of the giant dipole resonance to the shape degrees of freedom of superdeformed nuclei can split the vibration by approx.= 10 MeV, the lowest peak being expected at an excitation energy of approx.= 7-8 MeV and carrying approx.= 30% of the energy-weighted sum rule. (orig.)