Atoms

Special Issue Editor

Dr. Adam R. Vernon

E-Mail Website
Guest Editor

Massachusetts Institute of Technology, Cambridge, MA, USA
Interests: high-resolution laser spectroscopy; short-lived radioactive isotopes; atomic and molecular dynamics; efficient isotope separation; nuclear structure

Special Issue Information

Dear Colleagues,

It is now 100 years since the discovery of nuclear isomerism by Otto Hahn. Since then, we have discovered many species of nuclear isomers, states of atomic nuclei which have an abnormally long lifetime against decay due to the particular configuration of their nucleons. The extreme energy density stored in nuclear isomers (MeV/atom), intrinsic to the nuclear force, has made them tantalizing for a variety of applications, from nuclear batteries to gamma-ray lasers.

More recently, as radioactive ion beam facilities develop to allow studies of the limits of existence of atomic nuclei, understanding the details of the stabilizing phenomena of nuclear isomers is becoming increasingly important for fundamental nuclear physics and astrophysics research. Moreover, the advance in laser technology over the last few decades has provided renewed interest and increased opportunities to study and apply nuclear isomers using electron–nucleus interactions.

In this Special Issue, we will bring together original research papers, review articles, and short communications to provide an up-to-date view of the nuclear physics behind nuclear isomerism and bring attention to the present challenges and prospects for studies and applications of nuclear isomers, particularly those enabled by recent advances in atomic physics techniques.

Dr. Adam R. Vernon
Guest Editor

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Keywords

nuclear isomer
laser spectroscopy
nuclear clocks
nuclear battery
nucleosynthesis pathways
long-lived nuclear states

Published Papers (3 papers)

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Research

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7 pages, 323 KiB

Open AccessArticle

Search for Weak Side Branches in the Electromagnetic Decay Paths of the 6526-keV 10

^{+}

Isomer in ⁵⁴Fe

by Paul Böhm, Yuliia Hrabar, Dirk Rudolph, Pavel Golubev, Luis G. Sarmiento, Helena M. Albers, John T. Anderson, Michael A. Bentley, Michael P. Carpenter, Christopher J. Chiara, Patrick A. Copp, Ulrika Forsberg, Tianheng Huang, Heshani Jayatissa, Torben Lauritsen, Claus Müller-Gatermann, Xesus Pereira-Lopez, Walter Reviol, Darek Seweryniak, Sanna Stolze, Sivahami Uthayakumaar, Gemma L. Wilson and Jin Wu Show full author list Hide full author list

Atoms 2023, 11(9), 116; https://doi.org/10.3390/atoms11090116 - 24 Aug 2023

Viewed by 929

Abstract

High-spin nuclear isomers in

N \approx Z

nuclei between doubly magic

^{40}

Ca and

^{56}

Ni provide an excellent testing ground for the nuclear shell model and questions related to isospin symmetry breaking in the vicinity of the proton drip line. The purpose [...] Read more.

High-spin nuclear isomers in

N \approx Z

nuclei between doubly magic

^{40}

Ca and

^{56}

Ni provide an excellent testing ground for the nuclear shell model and questions related to isospin symmetry breaking in the vicinity of the proton drip line. The purpose of the present study is to investigate the possibility of weak electromagnetic decay branches along the decay paths of the 6526-keV

10^{+}

isomer in

^{54}

Fe. The isomer was strongly populated by means of the fusion-evaporation reaction

^{24}

Mg(

^{36}

Ar,

α 2 p

)

^{54 m}

Fe. The Gammasphere array was used to detect

γ

-ray cascades emitted from the isomeric state. By means of

γ γ γ

coincidences, weak non-yrast decay branches can be discriminated, with the isomer’s half-life confirmed at

T_{1 / 2} = 363 (4)

ns. The yrast

6_{1}^{+} \to 2_{1}^{+}

E 4

cross-over transition was interrogated. The observations are compared with shell-model calculations. Full article

(This article belongs to the Special Issue Over a Century of Nuclear Isomers: Challenges and Prospects)

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Figure 1

16 pages, 5924 KiB

Open AccessArticle

Setup for the Ionic Lifetime Measurement of the ^229mTh³⁺ Nuclear Clock Isomer

by Kevin Scharl, Shiqian Ding, Georg Holthoff, Mahmood Irtiza Hussain, Sandro Kraemer, Lilli Löbell, Daniel Moritz, Tamila Rozibakieva, Benedict Seiferle, Florian Zacherl and Peter G. Thirolf

Atoms 2023, 11(7), 108; https://doi.org/10.3390/atoms11070108 - 24 Jul 2023

Cited by 1 | Viewed by 1349

Abstract

For the realization of an optical nuclear clock, the first isomeric excited state of thorium-229 (^229mTh) is currently the only candidate due to its exceptionally low-lying excitation energy (

8.338 \pm 0.024

eV). Such a nuclear clock holds promise not only [...] Read more.

For the realization of an optical nuclear clock, the first isomeric excited state of thorium-229 (^229mTh) is currently the only candidate due to its exceptionally low-lying excitation energy (

8.338 \pm 0.024

eV). Such a nuclear clock holds promise not only to be a very precise metrological device but also to extend the knowledge of fundamental physics studies, such as dark matter research or variations in fundamental constants. Considerable progress was achieved in recent years in characterizing ^229mTh from its first direct identification in 2016 to the only recent observation of the long-sought-after radiative decay channel. So far, nuclear resonance as the crucial parameter of a nuclear frequency standard has not yet been determined with laser-spectroscopic precision. To determine another yet unknown basic property of the thorium isomer and to further specify the linewidth of its ground-state transition, a measurement of the ionic lifetime of the isomer is in preparation. Theory and experimental investigations predict the lifetime to be 10³–10⁴ s. To precisely target this property using hyperfine structure spectroscopy, an experimental setup is currently being commissioned at LMU Munich. It is based on a cryogenic Paul trap providing long-enough storage times for ^229mTh ions, that will be sympathetically cooled with ⁸⁸Sr⁺. This article presents a concept for an ionic lifetime measurement and discusses the laser-optical part of a setup specifically developed for this purpose. Full article

(This article belongs to the Special Issue Over a Century of Nuclear Isomers: Challenges and Prospects)

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Figure 1

Other

Jump to: Research

8 pages, 1602 KiB

Open AccessOpinion

Isomers in the Cosmos

by Eric B. Norman

Atoms 2023, 11(11), 140; https://doi.org/10.3390/atoms11110140 - 26 Oct 2023

Cited by 1 | Viewed by 1057

Abstract

The nucleosynthesis of chemical elements has been established to be the result of a variety of different types of nuclear reactions in stars. Under the extreme temperatures and densities encountered in such environments, nuclear isomers can be populated and thus complicate our understanding of these processes. In this paper, I have chosen to discuss five cases that illustrate how nuclear isomers can play important roles in the nucleosynthesis of chemical elements. Full article

(This article belongs to the Special Issue Over a Century of Nuclear Isomers: Challenges and Prospects)

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