Shape evolution of the hot giant dipole resonance

A systematic description of the evolution of the giant dipole resonance (GD R) at non-zero temperature T is given within the framework of two versions PDM-1 and PDM-2 of the Phonon Damping Model (PDM). The PDM interprets the d amping of the GDR as a result of coupling to all ph, pp and hh configuratio ns at T not equal 0, where the coupling to pp and hh configurations is deci sively important for an adequate description of the increase and saturation of the GDR width as a function of T. The numerical calculations have been performed for the GDR width, the strength function and the integrated yield of the gamma rays in Sn-120 and Pb-208 at 0 less than or equal to T less t han or equal to 6 MeV. The results obtained are found in a reasonable agree ment with the most recent experimental data for all these three characteris tics including the saturation of the yields within the GDR region and in th e region above it. Predictions have been made for the GDR shape in both nuc lei at T up to 6 MeV and for the integrated yield of gamma rays in Pb-208. (C) 1999 Elsevier Science B.V.