Deformation versus Sphericity in the Ground States of the Lightest Gold Isotopes
Deformation versus Sphericity in the Ground States of the Lightest Gold Isotopes
复制标题
最轻金同位素基态的变形与球形度
DOI：
10.1103/physrevlett.131.202501
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发表时间：
2023
影响因子：
8.6
通讯作者：
Cubiss J
中科院分区：
文献类型：
--
作者：
Cubiss J
在欧洲核子研究中心（CERN）的ISOLDE设施上，利用源内共振电离激光光谱技术测定了中子亏缺金核的电荷均方半径的变化。从这些新数据中，推断出核的变形，揭示了变形构型和球形构型之间的竞争。观察到同位素具有良好变形的基态，并且当移动到较轻的质量时，在中子极度缺乏的核素中可以看到突然转变为接近球形的形状。确定了一种形状共存和形状错开的情况，该情况具有不同变形的基态和异构体状态。这些新数据揭示了金同位素基态变形的独特模式，即当从重质量向轻质量移动时，在中子中壳周围存在一个变形良好的同位素平台，两侧是较重和较轻同位素的近球形形状——这一趋势迄今为止在核图的其他地方从未见过。利用D1M - Gogny相互作用和不同变形状态之间的组态混合，将实验电荷半径与Hartree-Fock-Bogoliubov计算结果进行了比较。计算结果受已知的金原子核的自旋、宇称和基态磁矩的约束，与实验结果吻合较好。
The changes in mean-squared charge radii of neutron-deficient gold nuclei have been determined using the in-source, resonance-ionization laser spectroscopy technique, at the ISOLDE facility (CERN). From these new data, nuclear deformations are inferred, revealing a competition between deformed and spherical configurations. The isotopesare observed to possess well-deformed ground states and, when moving to lighter masses, a sudden transition to near-spherical shapes is seen in the extremely neutron-deficient nuclides,. A case of shape coexistence and shape staggering is identified inwhich has a ground and isomeric state with different deformations. These new data reveal a pattern in ground-state deformation unique to the gold isotopes, whereby, when moving from the heavy to light masses, a plateau of well-deformed isotopes exists around the neutron midshell, flanked by near-spherical shapes in the heavier and lighter isotopes—a trend hitherto unseen elsewhere in the nuclear chart. The experimental charge radii are compared to those from Hartree-Fock-Bogoliubov calculations using the D1M Gogny interaction and configuration mixing between states of different deformation. The calculations are constrained by the known spins, parities, and magnetic moments of the ground states in gold nuclei and show a good agreement with the experimental results.