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Structural evolution of octupole-deformed radium isotopes within a coupled-channels method

Tao Wan1,2, Yibin Qian1,*, Chong Qi2,3,†, Ramon A. Wyss2, and Roberto J. Liotta2

  • *Contact author: qyibin@njust.edu.cn
  • †Contact author: chongq@kth.se
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Phys. Rev. C 113, 034313 – Published 11 March, 2026

DOI: https://doi.org/10.1103/vjnl-546y

Abstract

We have systematically investigated the spectroscopic properties in even-even Ra222−228 by introducing the cluster degrees of freedom within the coupled-channels method, which allows the core Pb208 to occupy the octupole 3− state (Calc. I), as well as both the octupole 3− and quadrupole 2+ states (Calc. II), along with multipole interactions. Excellent agreement has been achieved between our calculated results and available data on energy spectra, reduced electromagnetic Eλ transition-matrix elements, and intrinsic electric dipole, quadrupole, and octupole Qλ moments, pointing to the existence of strong octupole correlations in this region. The description of parity-doublet bands and electromagnetic-transition properties in both calculations is consistent with each other and with experimental data, which confirms the reliability of the coupled-channels formalism based on the cluster-core configuration in heavy nuclei. The enhanced E2 and E3 matrix elements in both calculations for Ra222−226 suggest that these three nuclei can exhibit static octupole deformation in both positive- and negative-parity bands. On the other hand, the accurate reproduction of the higher negative-parity bandhead and the derived Q3 moments in nucleus Ra228 is consistent with the interpretation of this nucleus as a deformed rotor exhibiting dynamic/soft octupole vibrations. We hope that the present work may open new avenues for exploring octupole collectivity and cluster correlations in heavy nuclei.

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Phys. Rev. C 113, 034313– Published 11 March, 2026
  • Received 20 November 2025
  • Revised 21 January 2026
  • Accepted 17 February 2026
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