  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 $^{120}$Sn and $^{208}$Pb, and are compared
with recent experimental data. Differences observed in the behavior of the
full-width-at-half-maximum of the GDR for $^{120}$Sn and $^{208}$Pb are
attributed to the fact that shell corrections in $^{208}$Pb are stronger than
in $^{120}$Sn, 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 $^{120}$Sn exhibits
effects due to the evaporation width of the compound nucleus, while these
effects are predicted for $^{208}$Pb.
