Systematic investigation of the high-$K$ isomers and the high-spin rotational bands in the neutron rich Nd and Sm isotopes by a particle-number conserving method

Abstract

The rotational properties of the neutron rich Nd and Sm isotopes with mass number $A\approx 150$ are systematically investigated using the cranked shell model with pairing correlations treated by a particle-number conserving method, in which the Pauli blocking effects are taken into account exactly. The 2-quasiparticle states in even-even Nd and Sm isotopes with excitation energies lower than 2.5~MeV are systematically calculated. The available data can be well reproduced and some possible 2 and 4-quasiparticle isomers are also suggested for future experiments. The experimentally observed rotational frequency variations of moments of inertia for the even-even and odd-$A$ nuclei are reproduced very well by the calculations. The effects of high-order deformation ${\epsilon }_6$ on the 2-quasiparticle excitation energies and moments of inertia of the ground state bands in even-even Nd and Sm isotopes are analyzed in detail. By analyzing the occupation probability $n_{\mu }$ of each cranked Nilsson orbitals near the Fermi surface and the contribution of each major shell to the angular momentum alignments, the alignment mechanism in these nuclei is understood clearly.

25 pages, 8 figures, 3 tables

References in corpus (7)

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Cited by in corpus (3)

• Rotational excitations in rare-earth nuclei: a comparative study within three cranking models with different mean fields and the treatments of pairing correlations
• Configuration and bandhead spin assignments for the 2-quasiparticle rotational bands in the neutron-rich nuclei ${}^{154,156}$Pm
• $K$-isomeric states in the isotopic and isotonic chains of ${}^{178}$Hf