Gamma Decay of Isovector Giant Resonances Built on Highly Excited States inSn111

Gamma-ray transition-energy spectra up to $E_{\gamma }\simeq 33$ MeV have been measured for the decay of the compound nucleus ${}_{}{}^{111}{}_{}{}^{}\mathrm{S}\mathrm{n}*$ populated at excitation energies up to $E^{*}\simeq 100$ MeV. Above $E_{\gamma }\simeq 20$ MeV an excess of gamma rays over the contribution from the isovector giant dipole resonance is observed in the energy range where the isovectors giant quadrupole resonance built on excited states is expected. The width of the giant dipole resonance in ${}_{}{}^{108,111}{}_{}{}^{}\mathrm{S}\mathrm{n}*$ shows a large increase with increasing nuclear temperature and angular momentum.