Search NASA⌕ Search
Home/Archive/DOE OSTI

DOE OSTI · 3003124

Evidence for triaxial shape coexistence in 74 Ge

Sensharma, N. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000250469451)·Ayangeakaa, A. D. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0000000316793175)·Kowalewski, T. M. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0000000174931842)·Janssens, R. V. F. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0000000170951715)·Wang, Y. M. [East China Normal University, Shanghai (China)]·Chen, Q. B. [East China Normal University, Shanghai (China)] (ORCID:0000000151594468)·Allmond, J. M. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000165338721)·Campbell, C. M. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000335774316)·Carmichael, S. R. [University of Notre Dame, IN (United States)] (ORCID:0000000274541876)·Carpenter, M. P. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000232375734)·Copp, P. [Argonne National Laboratory (ANL), Argonne, IL (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)]·Cousins, C. [University of Surrey (United Kingdom)] (ORCID:0009000838558217)·Devlin, M. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000269482154)·Garg, U. [University of Notre Dame, IN (United States)] (ORCID:0000000187514204)·Müller-Gatermann, C. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000291815568)·Hartley, D. J. [United States Naval Academy, Annapolis, MD (United States)] (ORCID:0000000162956815)·Heery, J. [University of Surrey (United Kingdom)] (ORCID:0000000230239907)·Henderson, J. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); University of Surrey (United Kingdom)] (ORCID:0000000260109644)·Jayatissa, H. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000187460234)·Johnson, S. R. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0009000434405070)·Kisyov, S. P. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000247187744)·Kondev, F. G. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000295675785)·Lauritsen, T. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000295600388)·Nandi, S. [Argonne National Laboratory (ANL), Argonne, IL (United States)]·Rathod, R. [University of Notre Dame, IN (United States)] (ORCID:0009000435704937)·Reviol, W. [Argonne National Laboratory (ANL), Argonne, IL (United States)]·Rocchini, M. [University of Guelph, ON (Canada); INFN Sezione di Firenze (Italy)] (ORCID:0000000168690181)·Rubino, E. [Michigan State University, East Lansing, MI (United States)]·Russell, R. [University of Surrey (United Kingdom)] (ORCID:0000000165800111)·Saracino, A. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0009000203572429)·Seweryniak, D. [Argonne National Laboratory (ANL), Argonne, IL (United States)]·Siciliano, M. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000245980298)·Wu, C. Y. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)] (ORCID:0000000157727196)
View original source ↗Read source document ↗Export metadata ↓

Abstract

The deformation properties of the low-lying states in 74 Ge have been investigated using multistep Coulomb excitation. The measurements were carried out with the advanced 𝛾-ray tracking array, GRETINA, and the CHICO2 particle detector. A comprehensive set of 𝐸⁢2 transition and diagonal matrix elements was deduced following an analysis with the semiclassical coupled-channels code GOSIA. The data were compared with results of calculations carried out within the framework of the generalized triaxial rotor model as well as with the configuration interaction shell model and the symmetric rotor model. Results from calculations with covariant density functional theory were used to construct a five-dimensional collective Hamiltonian for further comparisons with the data. Collectively, the calculations provide an accurate reproduction of the experimental matrix elements and further support an understanding in terms of the coexistence of two axially asymmetric shapes. In conclusion, this leads to an overall interpretation of the underlying structure of 74 Ge requiring triaxiality, as is also the case in the neighboring even-mass Ge isotopes.

Explore related subjects

59 ≤ A ≤ 89Multipole matrix elementsNuclear shapes and momentsNuclear structure & decaysRadiation detectorsmultipole matrix elementsnuclear shapes and momentsnuclear structure & decaysnuclear structure and decaysradiation detectors

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Sensharma, N. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000250469451), Ayangeakaa, A. D. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0000000316793175), Kowalewski, T. M. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0000000174931842), Janssens, R. V. F. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0000000170951715), Wang, Y. M. [East China Normal University, Shanghai (China)], Chen, Q. B. [East China Normal University, Shanghai (China)] (ORCID:0000000151594468), Allmond, J. M. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000165338721), Campbell, C. M. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000335774316), Carmichael, S. R. [University of Notre Dame, IN (United States)] (ORCID:0000000274541876), Carpenter, M. P. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000232375734), Copp, P. [Argonne National Laboratory (ANL), Argonne, IL (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)], Cousins, C. [University of Surrey (United Kingdom)] (ORCID:0009000838558217), Devlin, M. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000269482154), Garg, U. [University of Notre Dame, IN (United States)] (ORCID:0000000187514204), Müller-Gatermann, C. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000291815568), Hartley, D. J. [United States Naval Academy, Annapolis, MD (United States)] (ORCID:0000000162956815), Heery, J. [University of Surrey (United Kingdom)] (ORCID:0000000230239907), Henderson, J. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); University of Surrey (United Kingdom)] (ORCID:0000000260109644), Jayatissa, H. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000187460234), Johnson, S. R. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0009000434405070), Kisyov, S. P. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000247187744), Kondev, F. G. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000295675785), Lauritsen, T. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000295600388), Nandi, S. [Argonne National Laboratory (ANL), Argonne, IL (United States)], Rathod, R. [University of Notre Dame, IN (United States)] (ORCID:0009000435704937), Reviol, W. [Argonne National Laboratory (ANL), Argonne, IL (United States)], Rocchini, M. [University of Guelph, ON (Canada); INFN Sezione di Firenze (Italy)] (ORCID:0000000168690181), Rubino, E. [Michigan State University, East Lansing, MI (United States)], Russell, R. [University of Surrey (United Kingdom)] (ORCID:0000000165800111), Saracino, A. [University of North Carolina Chapel Hill, NC (United States); Duke University, Durham, NC (United States)] (ORCID:0009000203572429), Seweryniak, D. [Argonne National Laboratory (ANL), Argonne, IL (United States)], Siciliano, M. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000245980298), Wu, C. Y. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)] (ORCID:0000000157727196). 2025-08-04. Evidence for triaxial shape coexistence in 74 Ge. https://doi.org/10.1103/h839-vb3z

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

Total absorption spectroscopy of two isomers in 70 Cu influencing nucleosynthesis signatures

Isomers have long been known to be important for astrophysical nucleosynthesis processes, yet they are often neglected in network calculations due to computational limitations or lack of data. "Astromers" are astrophysically metastable nuclear states that can greatly impact nucleosynthesis pathways. In this work we show that astromers further impact the time-dependent electromagnetic signal during heavy element nucleosynthesis. In an experiment performed at the National Superconducting Cyclotron Laboratory, three 𝛽-decaying states of 70 Cu (6 − ground state, and two isomeric states: 3 − and 1 + ) were produced. 𝛽-feeding values were extracted from experimental spectra and compared to shell-model and QRPA+PVC calculations. Here, average 𝛾-ray energies from the 𝛽-decay events were incorporated into simulations of heavy element nucleosynthesis and were found to exhibit different energy release profiles over time, which may impact, in aggregate, time-dependent observable signals.

59 ≤ A ≤ 89↗
DOE OSTI2026

Collapse of Nuclear Collectivity along the 𝑁 = 𝑍 Line

The lifetime of the 𝐽 𝜋 = 2 + state in the self-conjugate 88 Ru nucleus has been determined in an experiment performed using rare-isotope beams provided by the new Facility for Rare Isotope Beams. This is the heaviest 𝑁 = 𝑍 nucleus for which such a measurement has been achieved. 88 Ru was populated by both one-neutron knockout and charge-exchange reactions, and the lifetime of 14.3$^{+2.5}_{−3.4}$ ps was determined using the triple-foil plunger technique. The extracted electromagnetic transition strength shows that the quadrupole collectivity has dropped significantly compared with the highly deformed 𝑁 = 𝑍 region around 𝐴 ∼ 80. These results are compared with state-of-the-art large-scale shell-model and discrete nonorthogonal shell-model calculations. The theoretical calculations indicate a moderate triaxial deformation and suggest that low-lying states in this nucleus are no longer dominated by strong many-particle many-hole excitations, unlike the lighter, highly deformed 𝑁 = 𝑍 nuclei nearby.

59 ≤ A ≤ 89↗
DOE OSTI2025

Constraining the Synthesis of the Lightest 𝑝 Nucleus 74 Se

We provide the first experimental cross section of the 73 As(p, γ) 74 Se reaction to constrain one of the main destruction mechanisms of the p nucleus 74 Se in explosive stellar environments. The measurement was done using a radioactive 73 As beam at incident energies of 3.1 and 3.7 MeV/nucleon. Along with the total cross section measurement, statistical properties of the 74 Se compound nucleus were extracted, constraining the reaction cross section across the entire Gamow window of the γ process. The impact of the experimentally constrained reaction rate on 74 Se production in Type II supernovae is investigated through Monte Carlo one-zone network simulations. The results indicate that the overproduction of 74 Se by Type II supernova models cannot be resolved by nuclear physics and point towards the description of the astrophysical conditions of the γ process.

59 ≤ A ≤ 89↗