Description of photoabsorption using photon strength function with the excitation of two resonance states

Abstract

The results of the use of photon strength function (PSF) of the model of two coupled damped oscillators (Two State Excitations, TSE) for the description of nuclear data for photoabsorption of electric dipole gamma-rays by atomic nuclei are presented. The response function widths dependent on gamma-ray energy were used instead of constant widths in the initial TSE model. It was demonstrated that such a phenomenological approach is a simple method for the description and prediction of the PSF with excitation of both low-energy (pigmy) dipole resonance (PDR) and high-energy giant dipole resonance (GDR). The best description of the experimental photoabsorption cross-sections is obtained at constant width in the PDR range and linear or quadratic energy-dependent width in the GDR range.