Average Radiation Widths and the Giant Dipole Resonance Width

Abstract

The average EL radiation width can be calculated in terms of the energy Eq and width Tq of the Giant Dipole Resonance (GDR). While various models can predict EG quite reliably, the theoretical situation regarding ΓG is much less satisfactory. We propose a simple phenomenological model which is able to provide ΓG values in good agreement with experimental data for spherical or deformed intermediate and heavy nuclei. In particular, this model can account for shell effects in ΓG, and can be used in conjunction with the droplet model. The ΓG values derived in such a way are used to compute average El radiation widths which are quite close to the experimental values. The method proposed for the calculation of ΓG also appears to be well suited when the GDR characteristics of extended sets of nuclei are required, as is namely the case in nuclear astrophysics.