Near-yrast structure of odd- A , neutron-rich Pr isotopes
Near-yrast structure of odd- A , neutron-rich Pr isotopes
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奇数A、富中子Pr同位素的近亚拉斯特结构
DOI：
10.1103/physrevc.85.044314
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发表时间：
2012
影响因子：
3.1
通讯作者：
Malkiewicz T
中科院分区：
文献类型：
--
作者：
Malkiewicz T
使用分别放置在EUROGAM-II和Gammasphere锗阵列内的Cm和Cf自发裂变源，通过瞬发射线光谱法研究了富中子镨同位素Pr和Pr。基于[541]态的转动带，具有相似的结构，已被分配给这些核。这些能带通过带内跃迁而衰减。在其他作品中报道的带间跃迁，没有观察到。在Lohengrin质谱仪上进行了核仁的延迟转换电子能谱和延迟转换射线能谱。一个35.1keV的Pr异构体已被确定为通过跃迁衰变，其半衰期为50（8）s。使用反射对称准粒子转子模型进行的计算成功地再现了这些原子核的激发态的能量及其衰变模式。通过与计算结果的比较，确定了该异构体的自旋为（1/2，3/2）。这种异构体的长半衰期和缺乏带内跃迁表明在所观察到的状态ofPr没有强八极相关。这可以解释为四极形变的增加减少了接近费米面的尼尔森轨道的数量，从而形成了八极集体。
The neutron-rich praseodymium isotopesPr andPr have been studied by prompt-ray spectroscopy usingCm andCf spontaneous-fission sources placed inside the EUROGAM-II and Gammasphere germanium arrays, respectively. Rotational bands based on[541] states, with similar structures, have been assigned to these nuclei. These bands decay by intrabandtransitions. Interbandtransitions, reported in other works, were not observed. Delayed conversion-electron and-ray spectroscopy of annucleus has been performed at the Lohengrin mass spectrometer. A previously reported 35.1-keV isomer ofPr has been determined to decay by antransition, and its half-life of 50(8)s has been measured. Calculations performed using a reflection-symmetric quasi-particle-rotor model successfully reproduce the energies of the excited states of these nuclei and their decay patterns. The spin of the isomer has been assigned to be (1/2, 3/2) from a comparison with the calculations. The long half-life of this isomer and the lack of intrabandtransitions show an absence of strong octupole correlations in the observed states ofPr. This is explained in terms of increasing quadrupole deformation reducing the number of Nilsson orbitals close to the Fermi surface available to form octupole collectivity.