多参考协变密度泛函理论下丰中子N=50同中子异荷素的低激发态
Low-lying states of neutron-rich $N=50$ isotones in multi-reference covariant density functional theory
- Jiangxi Normal University（江西师范大学）
- Chongqing Normal University（重庆师范大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
采用多参考协变密度泛函理论研究丰中子N=50同中子异荷素的低激发态，再现了⁷⁸Ni的低激发态，揭示了其结构的非单调演化，为该区域原子核结构提供了微观描述。
AI中文摘要：
丰中子N=50同中子异荷素（从⁸⁰Zn到⁷⁰Ca）的低激发态系统学预测存在显著的模型依赖性，而该区域实验信息仍十分匮乏。本研究采用基于相对论能量密度泛函的多参考协变密度泛函理论对这些原子核展开研究，其中核波函数被构造为具有不同四极形变的对称性恢复平均场态的叠加。研究合理再现了⁷⁸Ni的低激发态，除近球形基态外，还预测了基于第二0⁺态的长椭转动带。随着质子数向Z=20减小，低能结构呈现从球形到强形变再返回球形的非单调演化，这与价空间壳模型预测一致。特别地，⁷⁶Fe和⁷⁴Cr中形变基态的出现伴随四极集体性增强和更强的形状混合。该结果为从双幻核⁷⁸Ni到丰中子N=50同中子异荷素的结构演化提供了自洽的微观描述。
英文摘要：
Predictions for the systematics of low-lying states in neutron-rich $N=50$ isotones from \nuclide[80]{Zn} to \nuclide[70]{Ca}, where experimental information remains scarce, exhibit substantial model dependence. We investigate these nuclei using multi-reference covariant density functional theory based on a relativistic energy density functional, in which nuclear wave functions are constructed as superpositions of symmetry-restored mean-field states with different quadrupole deformations. The low-lying states of \nuclide[78]{Ni} are reasonably reproduced, and a prolate rotational band built on the second $0^+$ state is predicted in addition to a near-spherical ground state. As the proton number decreases toward $Z=20$, the low-energy structure exhibits a nonmonotonic evolution from spherical to strongly deformed and subsequently back to spherical shapes, consistent with valence-space shell-model predictions. In particular, the emergence of deformed ground states in \nuclide[76]{Fe} and \nuclide[74]{Cr} is accompanied by enhanced quadrupole collectivity and stronger shape mixing. The results provide a coherent microscopic description of the structural evolution from the doubly magic \nuclide[78]{Ni} to the neutron-rich $N=50$ isotones.
