Nuclear Photo-Reaction and Excitation Modes of Nuclei

Abstract

particle excitation and the core excitation. The careful comparison of the predictions by the single particle model with experimental data shows that these two types of excitation mode are distinguished in the photo-reaction of the light nuclei. It is indicated that the resonances observed in the (r, n) reactions of CI3, NI4 and FIg and NI4(r, p)CI3 in the energy region of 10~15 Mev are essentially due to the extra particle excitation. In the case of medium weight and heavy nuclei the resonances due to the extra particle excitation should appear, in many cases, at the energies lower than the thresholds for the (r, n) or (r, p) reactions. On the other hand, the giant resonance is characterized by the core excitation mode.· For the description of the core the possibility that the collective model may be rather reasonable than the simple independent particle model is indicated. And further, the distinction between these two models are discussed in detail.