<div class="csl-bib-body">
<div class="csl-entry">Muckenhuber, H., Welch, J. M., & Sterba, J. (2025, June 17). <i>Predicting molecular bond rupture induced by nuclear recoils</i> [Poster Presentation]. TCH Science Days 2025 – Faculty of Technical Chemistry, Wien, Austria. http://hdl.handle.net/20.500.12708/225839</div>
</div>
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/225839
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dc.description.abstract
For more than 100 years, nuclear transformations have driven key advances in chemistry,
such as discovering new elements, producing high levels of radioactivity, and enabling
applications in biology, geology, and medicine. In 1934, Szilard and Chalmers used thermal‐
neutron irradiation of ethyl iodide (C₂H₅I) to produce large activities of free ¹²⁸I-, showing
that prompt gamma-ray de-excitation of the excited nucleus can impart recoil energies
greater than the C–I bond energy and thus break the bond to release radioiodine.
However, ethyl iodide’s (radio-)chemical instability complicates quantitative retention
studies. To circumvent these challenges, we studied the metal-organic compound
tris(2,2,6,6-tetramethyl-3,5-heptandionato)chromium(III), or abbreviated Cr(tmhd)3. We
employed this compound because it meets the requirements for our technical application,
and it has been precisely studied regarding the retention, or the percentage of molecules
that can be found in the original chemical form after thermal neutron capture. Despite
recoil energies from gamma de-excitation far exceeding the ~2–3 eV Cr–O bond strength,
the experimentally observed retention of intact 51Cr(tmhd)₃ after thermal neutron capture
yields 7–8 % [2]. Despite the low survival fraction, a fundamental question arises: why does
the molecular disintegration not approach unity when recoil energies vastly outperform
bond dissociation thresholds?
Our starting point is the fundamental energy and momentum conservation for the nucleus
when emitting a gamma ray, as this is widely used in the literature to calculate retention.
Nuclear data from the IAEA provided transitions between energy levels and gamma
energies to calculate the recoils. In a simplified Monte Carlo approach, the calculated
retention amounts to 6.8%. A more sophisticated approach considering angular correlations
and branching ratios, the probability for a specific excited nuclear state, was used, but the
results of the previous calculations of retention could not be reproduced.
Future work will refine this framework by integrating nuclear and chemical properties to
develop a more comprehensive and accurate model of retention calculations. [1] Szilard L, Chalmers T A 1934 Nature 134 462
[2] Pichler V et al 2022 J Radioanal Nucl Chem 331 5067-5079
en
dc.description.sponsorship
FFG - Österr. Forschungsförderungs- gesellschaft mbH
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dc.language.iso
en
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dc.subject
Retention
en
dc.subject
Nuclear recoil
en
dc.subject
neutron activation analysis
en
dc.subject
Szilard Chalmers Effect
en
dc.title
Predicting molecular bond rupture induced by nuclear recoils
en
dc.type
Presentation
en
dc.type
Vortrag
de
dc.relation.grantno
201410202‐FV01, 2011205‐DV03
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dc.type.category
Poster Presentation
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tuw.project.title
COMET K2 Exzellenzzentrums für Tribologie
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tuw.researchinfrastructure
TRIGA Mark II-Nuklearreaktor
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tuw.researchTopic.id
C6
-
tuw.researchTopic.id
C1
-
tuw.researchTopic.name
Modeling and Simulation
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tuw.researchTopic.name
Computational Materials Science
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tuw.researchTopic.value
20
-
tuw.researchTopic.value
80
-
tuw.publication.orgunit
E057-14-2 - Fachgruppe Center for Labelling and Isotope Production (CLIP)
-
tuw.author.orcid
0000-0002-7883-8861
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tuw.event.name
TCH Science Days 2025 – Faculty of Technical Chemistry
en
tuw.event.startdate
17-06-2025
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tuw.event.enddate
18-06-2025
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tuw.event.online
On Site
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tuw.event.type
Event for scientific audience
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tuw.event.place
Wien
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tuw.event.country
AT
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tuw.event.presenter
Muckenhuber, Helmut
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wb.sciencebranch
Chemie
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wb.sciencebranch
Andere Naturwissenschaften
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wb.sciencebranch
Physik, Astronomie
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wb.sciencebranch.oefos
1040
-
wb.sciencebranch.oefos
1070
-
wb.sciencebranch.oefos
1030
-
wb.sciencebranch.value
35
-
wb.sciencebranch.value
20
-
wb.sciencebranch.value
45
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item.openairecristype
http://purl.org/coar/resource_type/c_18co
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item.fulltext
no Fulltext
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item.languageiso639-1
en
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item.grantfulltext
none
-
item.openairetype
conference poster not in proceedings
-
item.cerifentitytype
Publications
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crisitem.author.dept
E057-14-2 - Fachgruppe Center of Labelling and Isotope Production (CLIP)
-
crisitem.author.dept
E057-14-2 - Fachgruppe Center of Labelling and Isotope Production (CLIP)
-
crisitem.author.dept
E057-14-2 - Fachgruppe Center of Labelling and Isotope Production (CLIP)
-
crisitem.author.orcid
0000-0002-7883-8861
-
crisitem.author.parentorg
E057-14 - Fachbereich TRIGA Center Atominstitut
-
crisitem.author.parentorg
E057-14 - Fachbereich TRIGA Center Atominstitut
-
crisitem.author.parentorg
E057-14 - Fachbereich TRIGA Center Atominstitut
-
crisitem.project.funder
FFG - Österr. Forschungsförderungs- gesellschaft mbH
