Author:
Kolomietz Volodymyr,Lukyanov Sergiy,Shlomo Shalom
Abstract
AbstractThe validity of the small damping approximation (SDA) for the quasi-classical description of the averaged properties of nuclei at high temperatures is studied within the framework of collisional kinetic theory. The isoscalar collective quadrupole vibrations in hot nuclei are considered. We show that the extension of the SDA, by accounting for the damping of the distribution function δ f in the collision integral, reduces the rate of variation of distortion effects of the Fermi surface with temperature. The damping of the δ f in the collision integral increases the collisional width of the giant quadrupole resonance (GQR) significantly for small enough values of the relaxation time. The temperature dependence of the eigenenergy of the GQR becomes much weaker than in the corresponding SDA case.
Subject
General Physics and Astronomy
Reference32 articles.
1. K.A. Snover: “The giant dipole resonance at high excitation energy and spin”, Nucl. Phys., Vol. A553, (1993), pp. 153–171.
2. A. Bracco et al.: “Increase in Width of the Giant Dipole Resonance in Hot Nuclei: Shape Change or Collisional Damping?”, Phys. Rev. Lett., Vol. 74, (1995), pp. 3748–3751.
3. W.E. Ormand, P.F. Bortignon, R.A. Broglia and A. Bracco: “Behavior of the giant-dipole resonance in 120Sn and 208Pb at high excitation energy”, Nucl. Phys., Vol. A614, (1997), pp. 217–237.
4. F.V. De Blassio, W. Cassing, M. Tohyama, P.F. Bortignon and R.A. Broglia: “Nonperturbative study of the damping of giant resonances in hot nuclei”, Phys. Rev. Lett., Vol. 68, (1992), pp. 1663–1666.
5. V.M. Kolomietz, V.A. Plujko and S. Shlomo: “Interplay between one-body and collisional damping of collective motion in nuclei”, Phys. Rev., Vol. C54, (1996), pp. 3014–3024.