EXCITATION-ENERGY AND SPIN DEPENDENCE OF THE GIANT-DIPOLE RESONANCE AT FINITE TEMPERATURE

In order to investigate the evolution of the GDR from low to high excitation energies, a series of experiments, in which high energy gamma-rays were measured in heavy ion fusion reactions, have been performed at JAERI and at RIKEN. It has been confirmed that the width of the GDR increases rapidly for Ex greater-than-or-equal-to 100 MeV and our previously introduced GAMMA(E(x)) can explain the data well for 80 less-than-or-equal-to E(x) less-than-or-equal-to 120 MeV. The limiting temperature of the nucleus for existing of the GDR has been deduced for A approximately 70, 105 and 130. The GDR seems to disappear at the temperature of about a quarter of the resonance energy.