Giant resonances in exotic nuclear systems. What we expect and what we know

The characteristic features of γ-rays resulting from the decay of the Giant Dipole Resonance in very deformed, hot systems and in systems with a large isospin are discussed. For both cases there are recent theoretical predictions but very few if any data. With respect to hot, deformed systems it is argued that the discrepancy which exists between the measured and calculated asymmetry of the GDR γ-rays emitted in the fusion-fission process of hot actinide nuclei, might well be due to γ-emission during the saddle-to-scission stage of the fission process, that is from very deformed hot nuclear systems. The prospect of studying experimentally the behavior of Giant Resonances in systems with large isospin (= large neutron excess) is also discussed. Experiments on the GDR are feasible and will give information on the deformation of the emitting system. (author)