Exotic modes of excitation in atomic nuclei far from stability
Exotic modes of excitation in atomic nuclei far from stability
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DOI：
10.1088/0034-4885/70/5/r02
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发表时间：
2007-01
影响因子：
18.1
通讯作者：
N. Paar;D. Vretenar;E. Khan;G. Colò
中科院分区：
文献类型：
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作者：
N. Paar;D. Vretenar;E. Khan;G. Colò
我们回顾了最近在远离β稳定谷的原子核中集体激发演化的研究。集体自由度控制着核结构的基本方面，几十年来，对集体模态的研究，如旋转和振动，在我们理解核的复杂性质方面起着至关重要的作用。不稳定核的多极响应和弱束缚核系统中可能出现的新的奇异激发模式是一个迅速发展的研究领域，但迄今为止对这些现象的实验研究报道很少。在最近的实验中，已经收集了关于不稳定富中子核中低能偶极子响应演化的宝贵数据，但是现有的信息还不足以确定所观察到的激发的性质。即使在稳定的原子核中，巨大集体振荡的各种模式在观测到它们之前就已经被理论预测了很多年，因此，对远离稳定的原子核中集体激发模式的演化进行详细的理论研究是非常重要的。因此，我们讨论了近年来为描述弱束缚核中的集体激发而发展起来的现代理论工具。综述了这些模型在研究低能偶极子模式从稳定核到接近粒子发射阈值系统的演化过程中的应用，对各种等标量模式的分析，那些已经获得数据的模式，以及那些可以在未来实验中观察到的模式，对富中子核中的电荷交换模式及其演化的描述，以及对奇异低能模式在天体物理过程中的作用的研究。
We review recent studies of the evolution of collective excitations in atomic nuclei far from the valley of β-stability. Collective degrees of freedom govern essential aspects of nuclear structure, and for several decades the study of collective modes such as rotations and vibrations has played a vital role in our understanding of complex properties of nuclei. The multipole response of unstable nuclei and the possible occurrence of new exotic modes of excitation in weakly bound nuclear systems, present a rapidly growing field of research, but only few experimental studies of these phenomena have been reported so far. Valuable data on the evolution of the low-energy dipole response in unstable neutron-rich nuclei have been gathered in recent experiments, but the available information is not sufficient to determine the nature of observed excitations. Even in stable nuclei various modes of giant collective oscillations had been predicted by theory years before they were observed, and for that reason it is very important to perform detailed theoretical studies of the evolution of collective modes of excitation in nuclei far from stability. We therefore discuss the modern theoretical tools that have been developed in recent years for the description of collective excitations in weakly bound nuclei. The review focuses on the applications of these models to studies of the evolution of low-energy dipole modes from stable nuclei to systems near the particle emission threshold, to analyses of various isoscalar modes, those for which data are already available, as well as those that could be observed in future experiments, to a description of charge-exchange modes and their evolution in neutron-rich nuclei, and to studies of the role of exotic low-energy modes in astrophysical processes.