Behavior of the giant-dipole resonance in 120Sn and 208Pb at high excitation energy

Abstract

The properties of the giant-dipole resonance (GDR) are calculated as a function of excitation energy, angular momentum, and the compound nucleus particle decay width in the nuclei 120Sn and 208Pb, and are compared with recent experimental data. Differences observed in the behavior of the full-width-at-half-maximum of the GDR for 120Sn and 208Pb are attributed to the fact that shell corrections in 208Pb are stronger than in 120Sn, and favor the spherical shape at low temperatures. The effects shell corrections have on both the free energy and the moments of inertia are discussed in detail. At high temperature, the FWHM in 120Sn exhibits effects due to the evaporation width of the compound nucleus, while these effects are predicted for 208Pb.