Giant Resonance Of Exotic Nuclei

Cluster and halo are two important exotic structures for nuclei. The prop-erties of these exotic nuclear structures are profoundly affecting the cognition of nuclei. The nature of exotic nuclei is the focus and hot spot in the nucle-ar physics. Still, there are many unknown properties of exotic nuclei confusing scientists. The structures of clustered nuclei are difficult to measure directly in experiments. The concrete properties of nuclear cluster states are not clear. Peo-ple are searching for more heavier halo nuclei in lab. At the same time, people constantly develop various nuclear many body theories to describe and predict the structural properties of exotic nuclei more accurately.The giant dipole resonance of nuclei is a collective motion, which is a broad property over nuclide chart. This collective motion contains fruitful informa-tion of nuclei. The giant dipole resonance can be excited in many ways, such as Coulomb Excitation, photonuclear reaction, and nuclear collision. So it can easily be measured in experiments. Giant dipole resonance is an important and powerful tool for studying the nuclear properties, especially nuclear structure. From linear response theory, we derived the calculation formula of giant dipole cesonance’s cross section in an extension of Quantum Molecular Dynamics model. The method of the nonlinear property between the giant dipole resonance and the excitation energy is given. So the reliability of the giant dipole resonance spectrum’s calculations is ensured. In this model and theory frame, we study the giant dipole resonance properties of exotic nuclei in detail, and give a new method for measurement and analysis of nuclear exotic structures. For different cluster states of nuclei, we propose the concept of characteristic spectrum, and provide a clear method for experiments. For nuclear halo structures, we propose a method to measure the core of halo nuclei by giant dipole resonance spectra.The comparison of the calculated results and experimental results of GDR spectra for ground state of 12C shows that the ground state has the coexistence of non-cluster and triangular 3a clusters. For 160, the comparison shows that the ground state is of 4-α clusters with regular tetrahedral structure. Around the barrier of a break up(7.06A MeV), initialization give 8Be with double a structure, 12C with 3-α long chain structure,12C with 3-α triangle structure,16O with 4-α long chain structure,16O with 4-α kite structure,16O with 4-α square structure, The GDR spectra of different cluster states show significant characteristic peaks structure. The resonance peak at 31MeV corresponds to the minimum symmetry axis of a cluster’s degree of freedom in clustered nuclei, and this peak can be used as the probe for measuring the structure of a clusters in experiments. The lowest peak of GDR can be used to determine the distribution of nuclear matter in the maximum symmetry axis of clustered nuclei. The middle peaks of GDR can be used to distinguish the structure of the cluster states and the specific geometrical configurations. By analyzing the oscillation modes of each a in the cluster states, the phase relationship and the coupling law of the motions of the clusters are given, and the mechanism of the formations of characteristic spectra for different cluster structure is explained.The ratio of the halo nuclei initialized in EQMD model is proportional to the stability of the nuclei. The rationality of the halo nuclei’s phase space can be judged by the radial density distribution of nuclear material, the binding energy and the separation energy of valence nucleons. The widths of valence nucleons wave packet and the deformation of the core of halo nuclei are important for valence nucleon’s bound state. The core of 19C has a spherical structure, while the 22C core has a large ellipsoid deformation. The deformation structure of nuclear core causes the GDR spectra to split, and this phenomenon can be used to study the nuclear core of halo nuclei. The accuracy of the pygmy dipole resonance(PDR) spectra depend on the binding energy of valence nucleons. Due to the difficulty of the initialization of halo nuclei, the events of halo nuclei are still not enough. The properties of halo nuclei need to be studied Systematically.