Rotational excitations in rare-earth nuclei: A comparative study within three cranking models with different mean fields and treatments of pairing correlations
Rotational excitations in rare-earth nuclei: A comparative study within three cranking models with different mean fields and treatments of pairing correlations
复制标题
稀土原子核的旋转激发：具有不同平均场和配对相关性处理的三种启动模型的比较研究
DOI：
10.1103/physrevc.101.054303
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发表时间：
2020
影响因子：
3.1
通讯作者：
Afanasjev A. V
中科院分区：
文献类型：
--
作者：
Zhang Zhen-Hua;Huang Miao;Afanasjev A. V
用三种不同的核模型研究了稀土同位素Er （$Z=68$）、Tm （$Z=69$）和Yb （$Z=70$）的高自旋旋转带。这些是(i)通过Lipkin-Nogami （LN）方法具有近似粒子数投影的曲柄相对论Hartree-Bogoliubov （CRHB）方法，（ii）使用类壳模型方法（SLAP）或所谓的粒子数守恒（PNC）方法处理配对关联的曲柄协变密度泛函理论（CDFT），以及（iii）基于Nilsson势的曲柄壳模型（CSM），使用PNC方法处理配对关联。对这三种模型在描述均匀Er和Yb同位素的基态旋转带方面进行了详细的比较。讨论了这些模型在描述所研究的偶偶核的转动惯量、带交叉特征、平衡变形和配对能等方面的异同。这些量被认为是旋转频率和质子和中子数的函数。研究了该质量区中子数增加时第一带交叉性质的变化。平均而言，这些模型对现有实验数据的描述具有相当的准确性。然而，模型预测之间的差异在第一个波段交叉点以上变得更大。由于基于cdft的模型中数值计算的耗时性质，只有通过PNC-SCM才能系统地研究奇质量Tm核的基态和激发态带的旋转特性。除了少数例外，$^{165,167,169,171}$Tm中的实验1-准粒子带和3-准粒子带的旋转性质都得到了很好的再现。
High-spin rotational bands in rare-earth Er ($Z=68$), Tm ($Z=69$) and Yb ($Z=70$) isotopes are investigated by three different nuclear models. These are (i) the cranked relativistic Hartree-Bogoliubov (CRHB) approach with approximate particle number projection by means of the Lipkin-Nogami (LN) method, (ii) the cranking covariant density functional theory (CDFT) with pairing correlations treated by a shell-model-like approach (SLAP) or the so called particle-number conserving (PNC) method, and (iii) cranked shell model (CSM) based on the Nilsson potential with pairing correlations treated by the PNC method. A detailed comparison between these three models in the description of the ground state rotational bands of even-even Er and Yb isotopes is performed. The similarities and differences between these models in the description of the moments of inertia, the features of band crossings, equilibrium deformations and pairing energies of even-even nuclei under study are discussed. These quantities are considered as a function of rotational frequency and proton and neutron numbers. The changes in the properties of the first band crossings with increasing neutron number in this mass region are investigated. On average, a comparable accuracy of the description of available experimental data is achieved in these models. However, the differences between model predictions become larger above the first band crossings. Because of time-consuming nature of numerical calculations in the CDFT-based models, a systematic study of the rotational properties of both ground state and excited state bands in odd-mass Tm nuclei is carried out only by the PNC-SCM. With few exceptions, the rotational properties of experimental 1-quasiparticle and 3-quasiparticle bands in $^{165,167,169,171}$Tm are reproduced reasonably well.