The Gamma Decay of the GDR Under Extreme Conditions

The study of the γ decay from the giant dipole resonance (GDR) at finite temperature and far from stability allows to obtain information on the properties of nuclei in different regimes. Exclusive measurements of γ-decays with fusion reactions were made at LNL (INFN) in order to address different physical problems. First, the measurement of the temperature dependence of the GDR width up to T = 4 MeV in the mass region A = 130 will be shown together with its interpretation in terms of thermal shape fluctuation calculations. Secondly, a measurement of the isospin mixing for nuclei in the mass region A = 80 at temperature around T = 2 MeV is described. Finally the search for the pygmy dipole resonance in the neutron rich 68Ni nucleus, produced by fragmentation at GSI, will be presented. Coulomb excitation at 600 MeV/nucleon was employed and the γ-rays were detected with the RISING array.