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arXiv · 2106.04076

Evolution of octupole deformation and collectivity in neutron-rich lanthanides

K. Nomura·R. Rodríguez-Guzmán·L. M. Robledo·J. E. García-Ramos·N. C. Hernández
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Abstract

The onset of octupole deformation and its impact on related spectroscopic properties is studied in even-even neutron-rich lanthanide isotopes Xe, Ba, Ce, and Nd with neutron number $86\leqslant N\leqslant 94$. Microscopic input comes from the Hartree-Fock-Bogoliubov approximation with constrains on the axially symmetric quadrupole and octupole operators using the Gogny-D1M interaction. At the mean-field level, reflection asymmetric ground states are predicted for isotopes with neutron number around $N=88$. Spectroscopic properties are studied by diagonalizing the interacting boson model Hamiltonian, with the parameters obtained via the mapping of the mean-field potential energy surface onto the expectation value of the Hamiltonian in the $s$, $d$, and $f$ boson condensate state. The results obtained for low-energy positive- and negative-parity excitation spectra as well as the electric dipole, quadrupole, and octupole transition probabilities indicate the onset of pronounced octupolarity for $Z\approx 56$ and $N\approx 88$ nuclei.

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K. Nomura, R. Rodríguez-Guzmán, L. M. Robledo, J. E. García-Ramos, N. C. Hernández. 2021-10-23. Evolution of octupole deformation and collectivity in neutron-rich lanthanides. https://doi.org/10.1103/physrevc.104.044324

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