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Shape evolution of neutron-rich 106,108,110Mo isotopes in the triaxial degree of freedom

Journal Article · · Physical Review C
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  1. Seoul National Univ. (Korea, Republic of); RIKEN, Saitama (Japan). Nishina Center; OSTI
  2. RIKEN, Saitama (Japan). Nishina Center; Tohoku Univ., Sendai (Japan)
  3. RIKEN, Saitama (Japan). Nishina Center; Univ. of Brighton (United Kingdom)
  4. University of Tsukuba (Japan)
  5. Univ. of Brighton (United Kingdom)
  6. Seoul National Univ. (Korea, Republic of)
  7. Tohoku Univ., Sendai (Japan)
  8. RIKEN, Saitama (Japan). Nishina Center
  9. RIKEN, Saitama (Japan). Nishina Center; Univ. of Surrey, Guildford (United Kingdom); National Physical Lab., Teddington (United Kingdom)
  10. RIKEN, Saitama (Japan). Nishina Center; Beihang University, Beijing (China)
  11. Osaka Univ. (Japan)
  12. RIKEN, Saitama (Japan). Nishina Center; Univ. of Surrey, Guildford (United Kingdom)
  13. RIKEN, Saitama (Japan). Nishina Center; Univ. of York (United Kingdom)
  14. RIKEN, Saitama (Japan). Nishina Center; Peking Univ., Beijing (China)
  15. Univ. of Tokyo (Japan); University of Hong Kong (Hong Kong)
  16. Tohoku Univ., Sendai (Japan); RIKEN, Saitama (Japan). Nishina Center
  17. Univ. of Surrey, Guildford (United Kingdom)
  18. Institut Pluridisciplinaire Hubert Curien (IPHC), Strasbourg (France); Centre National de la Recherche Scientifique (CNRS), Paris (France). Institut National de Physique Nucléaire et de Physique des Particules; Université de Strasbourg (France)
  19. Laboratory of Subatomic Physics & Cosmology, Grenoble (France); Univ. of Grenoble Alpes (France); Centre National de la Recherche Scientifique (CNRS), Paris (France). Institut National de Physique Nucléaire et de Physique des Particules; Inst. Laue-Langevin (ILL), Grenoble (France)
  20. GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany)
  21. University of Sofia (Bulgaria)
  22. Peking Univ., Beijing (China)
  23. Institut Pluridisciplinaire Hubert Curien (IPHC), Strasbourg (France); Centre National de la Recherche Scientifique (CNRS), Paris (France). Institut National de Physique Nucléaire et de Physique des Particules; Université de Strasbourg (France); Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Orsay (France); Université Paris-Sud (France)
  24. Univ. of Surrey, Guildford (United Kingdom); National Physical Lab., Teddington (United Kingdom)
  25. Laboratory of Subatomic Physics & Cosmology, Grenoble (France); Univ. of Grenoble Alpes (France); Centre National de la Recherche Scientifique (CNRS), Paris (France). Institut National de Physique Nucléaire et de Physique des Particules
  26. RIKEN, Saitama (Japan). Nishina Center; Univ. Autonoma de Madrid (Spain); Instituto de Estructura de la Materia, Madrid (Spain)
  27. Yale Univ., New Haven, CT (United States); Technische Univ. Darmstadt (Germany)
  28. National Inst. of Nuclear Physics (INFN), Milan (Italy)
+ Show Author Affiliations
Background: Neutron-rich nuclei with mass number between 100 and 110 attract much attention, since several kinds of shapes, such as spherical, prolate, oblate, and triaxial shapes, are predicted. In particular, for neutron-rich Mo isotopes, different models predict different magnitudes and rigidity of triaxial deformation. Previous interpretations of experimental results based solely on low-lying $$2^+_2$$ states are insufficient to distinguish between the rigid triaxial shape, $$\gamma$$ vibration, or $$\gamma$$-soft rotor. Purpose: The shape evolution of 106Mo, 108Mo, and 110Mo is investigated through their $$2^+_1$$-state lifetimes, decay-branching ratios of the $$2^+_2$$ state, and energies of the low-lying collective excited states with $K^π = 0^+, 2^+$, and $4^+$. Method: $$\beta$$-delayed $$\gamma$$-ray spectroscopy was employed for neutron-rich Nb and Zr isotopes produced at the RIKEN RI Beam Factory to populate excited states in 106Mo, 108Mo, and 110Mo. The EUroball-RIKEN Cluster Array was used for high-resolution $$\gamma$$-ray detection and lifetimes of the $$2^+_1$$ states were determined using the UK fast-timing array of LaBr3(Ce) detectors. Results: New $$\gamma$$-ray transitions and levels are reported, including newly assigned $$0^+_2$$ states in 108,110Mo. Quadrupole deformations were obtained for 106,108,110Mo from their $$2^+_1$$ energies and lifetimes. The $$\beta$$-delayed neutron-emission probabilities of 108Nb and 110Nb were determined by examining the $$\gamma$$ rays of their respective daughter decays. Conclusions: In this work, the even-odd energy staggering in the $$2^+_2$$ band was compared with typical patterns of the $$\gamma$$-vibrational band, rigid triaxial rotor, and $$\gamma$$-soft rotor. The very small even-odd staggering of 106Mo, 108Mo, and 110Mo favors a $$\gamma$$-vibrational band assignment. The kinematic moment of inertia for the $$2^+_2$$ band showed a trend similar to the ground-state band, which is as expected for the $$\gamma$$-vibrational band. Beyond-mean-field calculations employing the constrained Hartree-Fock-Bogoliubov and local quasiparticle-random-phase approximation method using the SLy5 + T interaction reproduced the ground and $$2^+_2$$ bands in 106Mo and 108Mo. The collective wave functions are consistent with the interpretation of the $$2^+_2$$ band as the $$\gamma$$-vibrational band of the prolate shape. However, the staggering pattern observed in 110Mo differs from the one suggested in the calculations which predict a $$\gamma$$-soft rotor. There was no experimental indication of the oblate shape or the $$\gamma$$-soft rotor predicted in these Mo isotopes.
Research Organization:
Yale Univ., New Haven, CT (United States)
Sponsoring Organization:
Federal Ministry of Education and Research (BMBF); Japan Society for the Promotion of Science (JSPS); Ministry of Science and Innovation (MICINN); National Research Foundation of Korea (NRF); Science and Technology Facilities Council (STFC); UK National Measurement Office (NMO); USDOE; USDOE Office of Science (SC)
Grant/Contract Number:
FG02-91ER40609
OSTI ID:
1800744
Alternate ID(s):
OSTI ID: 1615533
Journal Information:
Physical Review C, Journal Name: Physical Review C Journal Issue: 4 Vol. 101; ISSN 2469-9985
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English

References (55)

Transition Probability from the Ground to the First-Excited 2+ State of Even–Even Nuclides journal May 2001
Review Of LogftValues In β Decay journal July 1998
Level structure of106Mo journal March 1983
The Beta decay of104Nb and the level scheme of104Mo journal June 1982
The first excited 0+-state in104Mo journal June 1979
Rotational states in even atomic nuclei journal September 1958
Signatures of γ softness or triaxiality in low energy nuclear spectra journal May 1991
A study of the neutron-rich isotopes near A = 100 by means of the (t, p) reaction journal April 1972
In-flight RI beam separator BigRIPS at RIKEN and elsewhere in Japan journal May 2003
Equilibrium shapes and high-spin properties of the neutron-rich A ≈ 100 nuclei journal May 1997
Tables of E2 transition probabilities from the first 2 + states in even–even nuclei journal January 2016
Evaluation of theoretical conversion coefficients using BrIcc
  • Kibédi, T.; Burrows, T. W.; Trzhaskovskaya, M. B.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 589, Issue 2 https://doi.org/10.1016/j.nima.2008.02.051
journal May 2008
Installation and commissioning of EURICA – Euroball-RIKEN Cluster Array
  • Söderström, P. -A.; Nishimura, S.; Doornenbal, P.
  • Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 317 https://doi.org/10.1016/j.nimb.2013.03.018
journal December 2013
Improvement of correlation between a β ray and its parent nucleus in β-decay spectroscopy using RI beams journal January 2020
A systematical study of neutron-rich Zr isotopes by the projected shell model journal May 2011
Development of axial asymmetry in the neutron-rich nucleus 110Mo journal October 2011
Lifetime measurements of the first 2 + states in 104,106Zr: Evolution of ground-state deformations journal November 2015
Observation of Rotational Bands in Neutron-Rich 106 Mo Nucleus journal February 2002
The AME2016 atomic mass evaluation (II). Tables, graphs and references journal March 2017
${K^\pi=5^-}$ rotational bands in neutron-rich Mo, Ru, and Pd nuclei journal July 2019
BigRIPS separator and ZeroDegree spectrometer at RIKEN RI Beam Factory journal January 2012
Beta-gamma spectroscopy at RIBF journal January 2012
Surface Oscillations in Even-Even Nuclei journal May 1956
Coupling of Angular Momenta in Odd-Odd Nuclei journal September 1958
Decay properties of neutron-rich niobium isotopes journal July 1976
Structure of highly deformed Zr 102 populated in decay of low- and high-spin isomers of Y 102 journal June 1991
Prompt γ-ray spectroscopy of the Mo 104 and Mo 108 fission fragments journal March 1996
First observation of β decay of Nb 108 to Mo 108 journal November 1996
Oblate stability of A ≈ 110 nuclei near the r -process path journal January 2002
Half-life measurements of several states in Sr 95 , 97 , Zr 97 , 100 , 104 , Mo 106 , and Ce 148 journal April 2006
Triaxiality in Mo 105 and Mo 107 from the low to intermediate spin region journal December 2006
β-decay half-lives and β -delayed neutron emission probabilities of nuclei in the region A ≲ 110 , relevant for the r process journal March 2009
Microscopic description of large-amplitude shape-mixing dynamics with inertial functions derived in local quasiparticle random-phase approximation journal December 2010
Exact diagonalization of the Bohr Hamiltonian for rotational nuclei: Dynamical γ softness and triaxiality journal June 2011
Shape fluctuations in the ground and excited 0 + states of 30 , 32 , 34 Mg journal December 2011
Shape transition and fluctuations in neutron-rich Cr isotopes around N = 40 journal August 2012
Shape evolution in 116 , 118 Ru: Triaxiality and transition between the O(6) and U(5) dynamical symmetries journal August 2013
First observation of a rotational band and the role of the proton intruder orbital π 1/2 + [431] in very neutron-rich odd-odd Nb 106 journal April 2014
Theoretical study of triaxial shapes of neutron-rich Mo and Ru nuclei journal September 2015
Lifetime measurement of neutron-rich even-even molybdenum isotopes journal March 2017
Multipole modes of excitation in triaxially deformed superfluid nuclei journal October 2017
Experimental study of the lifetime and phase transition in neutron-rich Zr 98 , 100 , 102 journal November 2017
Structural Evolution in the Neutron-Rich Nuclei Zr 106 and Zr 108 journal May 2011
β -Decay Half-Lives of 110 Neutron-Rich Nuclei across the N = 82 Shell Gap: Implications for the Mechanism and Universality of the Astrophysical r Process journal May 2015
Are There Signatures of Harmonic Oscillator Shells Far from Stability? First Spectroscopy of Zr 110 journal January 2017
Experimental Information Concerning Deformation of Neutron Rich Nuclei in the A ∼ 100 Region journal July 1970
Harmonic Two-Phonon γ-Vibrational State in Neutron-Rich 106 Mo journal September 1995
Beta-Decay Half-Lives and Neutron-Emission Probabilities of Very Neutron-Rich Y to Tc Isotopes journal July 1996
Collective bands in 104,106,108Mo journal July 2006
First observation of excited states in the 110Mo nucleus journal June 2004
E2/M1 mixing ratios in transitions from the gamma vibrational bands to the ground state rotational bands of 102, 104, 106, 108Mo, 108, 110, 112Ru, and 112, 114, 116Pd journal February 2018
Soft chiral vibrations in 106Mo journal August 2005
100 Mo( t , p ) 102 Mo Reaction at 15.8 MeV journal May 1973
Gamma-ray Spectroscopy in the Vicinity of $^{108}$Zr journal January 2015
β Decay Half-Lives of A ∼ 110 Nuclei on the r -Process Path conference June 2015

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