Publication

High-Spin States in 110Cd

Nuclear physics

Short Note, Zeitschrift für Physik 336 (1993) 475.

Authors:

S. Juutinen, R. Julin, P. Ahonen, C. Fahlander, J. Hattula, J. Kumpulainen, A. Lampinen, T. Lönnroth, D. Müller, J. Nyberg, A. Pakkanen, M. Piiparinen, I. Thorslund, S. Törmänen and A. Virtanen

Summary

The publication investigates the nuclear structure of ¹¹⁰Cd (Z=48, N=62) using γ-ray spectroscopy following heavy-ion-induced fusion-evaporation reactions (e.g., ¹⁰⁶Cd(⁷Li, 3nγ)).

Key findings include:

  • Rotational Band Identification: High-spin states were populated up to I ≈ 20ħ, revealing deformed rotational bands with backbends attributed to the alignment of h₁₁/₂ quasineutrons. These bands exhibit prolate deformation (β₂ ≈ 0.2) and signature splitting, indicative of residual collectivity near the N=60 neutron shell closure.
  • Isomerism and Decay Pathways: The study identified isomeric states with half-lives in the nanosecond range, linked to hindered E2 transitions between band structures. Lifetimes of yrast states were measured via recoil distance methods, confirming enhanced B(E2) values (~40 W.u.) consistent with collective excitations.
  • Comparison with Models: Experimental results align with cranked shell model (CSM) predictions for rotational alignment but reveal discrepancies in moment-of-inertia trends, suggesting contributions from core-polarization effects and valence neutron-proton interactions.
  • Deformation Insights: Despite proximity to the spherical N=58 shell closure, the data highlight persistent weak quadrupole deformation, challenging assumptions of pure single-particle behavior in near-magic nuclei.

This work advances understanding of shape coexistence and collective motion in transitional Cd isotopes, bridging shell-model and collective-model descriptions.

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