イッテルビウム150で希少な核異性体を初観測、核構造研究を前進（Physicists Observe Rare Nuclear Isomer in Ytterbium-150 for First Time, Advancing Nuclear Structure Research）

2026-03-11 中国科学院（CAS）

Figure 1. Occurrence of 8+, 10+, and 12+ isomers on the partial nuclear chart. (Image by Physical Review Letters)

＜関連情報＞

• https://english.cas.cn/newsroom/research-news/202603/t20260312_1152431.shtml
• https://journals.aps.org/prl/abstract/10.1103/6cjc-bhfg

発見＝1⁢0+異性体150Yb: 最長の性質10+異性体鎖 Discovery of an =1⁢0+ Isomer in 150Yb: Nature of the Longest 10+ Isomeric Chain

W. Q. Zhang, Z. Liu, A. N. Andreyev, Y. X. Yu, G. J. Fu, C. Qi, H. Huang, X. H. Yu, P. M. Walker et al.
Physical Review Letters  Published: 26 February, 2026
DOI: https://doi.org/10.1103/6cjc-bhfg

Abstract

Delayed -ray spectroscopy was performed for evaporation residues produced in the ⁵⁸Ni+⁹⁶Ru reaction. A new isomer in    ⁷⁰₁₅₀Yb (Z=70, N=80) with a half-life of 0.62⁢(5)  μ⁢s was identified at an excitation energy of 2872(2) keV. Its spin-parity is assigned as (10⁺) and a decay scheme is proposed based on a strong analogy with that of the isotonic    ⁶⁸₁₄₈Er. Previously, the 10⁺ isomers were observed in the N=80 even- isotones from the neutron-rich    ⁴⁶₁₂₆Pd to the neutron-deficient    ⁶⁸₁₄₈Er. For the first time, by combining experimental data and comprehensive large-scale shell-model calculations, we clearly identify the configurations of these isomers and demonstrate that they all exhibit seniority structures. These findings firmly establish a configuration change in the 10⁺ isomeric chain, from a pair of maximally aligned 1⁢ℎ_11/2 neutrons (holes) to a pair of maximally aligned 1⁢ℎ_11/2 protons around the Z=64 subshell closure. This transition serves as a unique isomeric relay underpinning the persistence of the isomeric chain.