Study of pre-equilibrium contribution to total absorption cross section in some samarium isotopes using exciton model

Photonuclear reactions were studied for the samarium isotopes 144Sm, 148Sm, 150Sm, 152Sm, and 154Sm over an energy range of 8–22 MeV using the EMPIRE 3.2.2 nuclear reaction code. Total photoabsorption cross sections, particularly the Giant Dipole Resonance (GDR), were analyzed by considering contributions from both compound-nucleus and pre-equilibrium mechanisms. The Hauser–Feshbach model was employed to describe the compound-nucleus contribution, while the exciton model was used for the pre-equilibrium process. The results showed that the compound-nucleus mechanism is dominant across the studied energy range, although pre-equilibrium effects become more noticeable at higher energies. Furthermore, the influence of various gamma-ray strength function models, including MLO and EGLO, was evaluated. It was observed that different MLO variants yield consistent results, whereas the EGLO model fails to reproduce the double-peaked GDR structure characteristic of deformed samarium isotopes. These findings contribute to a better understanding of photonuclear reaction mechanisms and the applicability of gamma-ray strength function models in nuclear structure studies.