The quest of shape coexistence in Zr isotopes

Abstract

The mass region with A~100 and Z~40 is known to experience a sudden onset of deformation. The presence of the subshell closure $Z=40$ makes feasible to create particle-hole excitations at a moderate excitation energy and, therefore, likely intruder states could be present in the low-lying spectrum. In other words, shape coexistence is expected to be a key ingredient to understand this mass region. The aim of this work is to describe excitation energies, transition rates, radii, and two-neutron separation energies for the even-even 94-110Zr nuclei and, moreover, to obtain information about wave functions and deformation. The interacting boson model with configuration mixing will be the framework to study the even-even Zr nuclei, considering only two types of configurations: 0particle-0hole and 2p-2h excitations. On one hand, the parameters appearing in the Hamiltonian and in the E2 transition operator are fixed trough a least-squares fit to the whole available experimental information. On the other hand, once the parameters have been fixed, the calculations allow to obtain a complete set of observables for the whole even-even Zr chain of isotopes. Spectra, transition rates, radii, ${\rho }^2(E0)$, and two-neutron separation energies have been calculated and a good agreement with the experimental information has been obtained. Moreover, a detailed study of the wave function has been conducted and mean-field energy surfaces and deformation have been computed too. The importance of shape coexistence has been shown to correctly describe the A~100 mass area for even-even Zr nuclei. This work confirmed the rather spherical nature of the ground state of 94-98Zr and its deformed nature for 100-110Zr isotopes. The sudden onset of deformation in 100Zr is owing to the rapid lowering of a deformed (intruder) configuration which is high-lying in lighter isotopes.

Submitted to PRC

References in corpus (14)

• Configuration mixing of angular-momentum and particle-number projected triaxial HFB states using the Skyrme energy density functional
• Beyond Mean-Field Calculations for Odd-A Nuclei
• First Measurement of Collectivity of Coexisting Shapes based on Type II Shell Evolution: The Case of ${}^{96}$Zr
• Structural evolution in $A\approx 100$ nuclei within the mapped interacting boson model based on the Gogny energy density functional
• Symmetry conserving configuration mixing method with cranked states
• The Pt isotopes: comparing the Interacting Boson Model with Configuration Mixing and the Extended Consistent-Q formalism
• Intertwined Quantum Phase Transitions in the Zr Isotopes
• Evidence for coexisting shapes in ${}^{98}$Zr through lifetime measurements
• Shell model based deformation analysis of light Cadmium isotopes
• Consistent description of nuclear charge radii and electric monopole transitions
• Configuration mixing in the neutron-deficient ${}^{186-196}$Pb isotopes
• Nuclear deformation at finite temperature
• Description of shape coexistence in ${}^{96}$Zr based on the collective quadrupole Bohr Hamiltonian
• Nuclear deformation in the laboratory frame

Cited by in corpus (23)

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• Zr Isotopes as a region of intertwined quantum phase transitions
• The subtle connection between shape coexistence and quantum phase transition. The Zr case
• Tests of collectivity in ${}^{98}$Zr by absolute transition rates
• Signatures for shape coexistence and shape/phase transitions in even-even nuclei
• Nuclear shape evolution and shape coexistence in Zr and Mo isotopes
• Mixed configurations and intertwined quantum phase transitions in odd-mass nuclei
• Shape coexistence in Sr isotopes
• Shape phase transitions in odd-A Zr isotopes
• Interplay between pairing and triaxial shape degrees of freedom in Os and Pt nuclei
• Description of the low-lying collective states of ${}^{96}$Zr based on the quadrupole-collective Bohr Hamiltonian
• Systematic Trends of 0${}_2^{+}$, 1${}_1^{-}$, 3${}_1^{-}$ and 2${}_1^{+}$ Excited States in Even-Even Nuclei
• An implementation of nuclear time-dependent density-functional theory and its application to the nuclear isovector electric dipole resonance
• Evolution of the phenomenologically determined collective potential along the chain of Zr isotopes
• Single-particle and collective structures in neutron-rich Sr isotopes
• Enlarged deformation region in neutron-rich Zr isotopes by the second intruder orbit
• Shape evolution in even-mass ${}^{98-104}$Zr isotopes via lifetime measurements using the $\gamma \gamma$-coincidence technique
• Two-neutron transfer reactions as a tool to study the interplay between shape coexistence and quantum phase transitions
• Coupling between collective modes in the deformed ${}^{98}$Zr nucleus: Insights from consistent HFB+QRPA calculations with the Gogny interaction
• Intertwined quantum phase transitions in odd-mass Nb isotopes
• A Nuclear Periodic Table
• Influence of triaxiality on the description of low-energy excitation spectrum of ${}^{96}$Zr