Assessing hand-held Raman spectrometer FirstDefender RM for nuclear safeguards applications

Berlizov, A. B.; Ho, Doris Mer Lin; Nicholl, Adrian; Fanghänel, Thomas; Mayer, Klaus

doi:10.1007/s10967-015-4160-z

Cited by 9 publications

(6 citation statements)

References 14 publications

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“…The variation in published Raman spectra of uranyl hydroxide species was one of the motivations for this study. Raman spectra of uranyl hydroxide species typically have a peak attributed to the symmetric uranyl stretching mode in the 830–855 cm –1 range, as well as peaks near 550 and 450 cm –1 , but the spectra are highly inconsistent, even when the same structural form is purportedly being observed. ,,− Variation among samples of natural schoepite and metaschoepite can be partially explained by the likely presence of minor impurities. However, this variation persists among synthetic uranyl hydroxide hydrates as well. ,, Part of the variation is due to the fact that producing pure synthetic uranyl hydroxide species is difficult.…”

Section: Discussionmentioning

confidence: 87%

“…Alam et al also observed a doublet shape in the uranyl stretching region of the Raman spectrum of synthetic metaschoepite, but both peaks were significantly lower in energy . Other spectra of “schoepite” or “uranyl hydroxide” differ significantly and do not even share qualitative similarities in the uranyl stretching region. − …”

Section: Discussionmentioning

confidence: 99%

“…The vibrational properties of these uranyl hydroxide minerals and their synthetic analogues have been characterized several times, but inconsistencies exist between data sets, likely due to variation in synthesis, experimental techniques, and storage conditions (Figure S1). ,− Furthermore, a lack of correlation between structural and vibrational data makes it difficult to interpret these differences and assign the observed vibrational modes to specific motions. To remove this uncertainty, in this study, the same samples of synthetic metaschoepite and its dehydration product have been interrogated using multiple diffraction and spectroscopic techniques.…”

Section: Introductionmentioning

confidence: 99%

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Elucidation of the Structure and Vibrational Spectroscopy of Synthetic Metaschoepite and Its Dehydration Product

et al. 2019

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We confirm that synthetic uranyl hydroxide hydrate metaschoepite [(UO)24O(OH)6]·5H2O is unstable against dehydration under dry conditions, and we present a structural and vibrational spectroscopic study of synthetic metaschoepite and its ambient temperature dehydration product. Complementary structural (X-ray diffraction and neutron diffraction) and vibrational spectroscopic techniques (Raman spectroscopy, infrared spectroscopy, and inelastic neutron scattering) are used to probe different components of these species. Analysis of the dehydration product suggests that it contains both pentagonally coordinated and hexagonally coordinated uranyl ions, necessitating that some uranyl ions undergo a coordination change during the dehydration of pentagonally coordinated metaschoepite. Vibrational spectra of metaschoepite and its dehydration product are interpreted with power spectra generated from ab initio molecular dynamics trajectories, allowing assignment of all major features. We identify the uranyl symmetric stretching modes of the four distinct uranyl ions in synthetic metaschoepite and clarify the assignment of lower energy Raman modes in both structures. The coanalysis of experimental and computational data reveals a strong coupling between the uranyl stretching modes and hydroxide bending modes in the anhydrous structure, leading to the presence of several high-energy combination bands in the inelastic neutron scattering data.

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Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Elucidation of the Structure and Vibrational Spectroscopy of Synthetic Metaschoepite and Its Dehydration Product

et al. 2019

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“…Diuranate compounds (X 2 U 2 O 7 ), particularly sodium and ammonium forms, are also important U(VI) oxides because they are precipitated as an intermediate product during the production of yellowcake and nuclear fuel pellets [81]. The main spectroscopic band associated with uranyl in Na 2 U 2 O 7 is located between 789 and 778 cm −1 , whereas the NH 4 form ((UO 2 (OH) 2−x (O)(NH 4 ) x )·yH 2 O) exhibits bands within a larger spectral window (841–804 cm −1 ) due to hydrolysis and variability in hydration that occurs between synthetic batches [82,83]. Only one other U(VI) oxide phase, the rare mineral Vorlanite (Ca,U(VI)O 4 ), has been reported in the literature.…”

Section: Chemical and Structural Elucidation Of Uranium Solid-state Cmentioning

confidence: 99%

Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy

Haes

Forbes

2018

Coordination Chemistry Reviews

133

128

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The purpose of this review is to provide an overview of uranium speciation using vibrational spectroscopy methods including Raman and IR. Uranium is a naturally occurring, radioactive element that is utilized in the nuclear energy and national security sectors. Fundamental uranium chemistry is also an active area of investigation due to ongoing questions regarding the participation of 5f orbitals in bonding, variation in oxidation states and coordination environments, and unique chemical and physical properties. Importantly, uranium speciation affects fate and transportation in the environment, influences bioavailability and toxicity to human health, controls separation processes for nuclear waste, and impacts isotopic partitioning and geochronological dating. This review article provides a thorough discussion of the vibrational modes for U(IV), U(V), and U(VI) and applications of infrared absorption and Raman scattering spectroscopies in the identification and detection of both naturally occurring and synthetic uranium species in solid and solution states. The vibrational frequencies of the uranyl moiety, including both symmetric and asymmetric stretches are sensitive to the coordinating ligands and used to identify individual species in water, organic solvents, and ionic liquids or on the surface of materials. Additionally, vibrational spectroscopy allows for the in situ detection and real-time monitoring of chemical reactions involving uranium. Finally, techniques to enhance uranium species signals with vibrational modes are discussed to expand the application of vibrational spectroscopy to biological, environmental, inorganic, and materials scientists and engineers.

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“…For nuclear chemical forensics, the formation of hydrates and oxides of pure, anhydrous UF 4 could be relevant to understanding the environmental exposure of the material, and the environmental behavior of UF 4 itself is relevant for material stewardship applications. Optical vibrational spectroscopy is an important tool for identifying the chemical composition of materials and is used extensively in all material analysis fields, including chemical forensics, − fuel material production, − and environmental chemistry. , Optical spectroscopy obeys certain selection rules, so Raman and IR scattering probe only a subset of the full vibrational spectrum. In particular, librational modes of water in crystal hydrates are usually not observable using Raman and IR spectroscopies.…”

Section: Introductionmentioning

confidence: 99%

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF₄(H₂O)_2.5

et al. 2021

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Uranium tetrafluoride hydrate (UFH) is formed by immersing anhydrous UF4 under water for 12 h. UFH is therefore clearly a chemical species of environmental concern, as anhydrous UF4 is an intermediate uranium form in the nuclear fuel cycle. We use inelastic neutron scattering (INS) to probe the full vibrational spectra of UFH and its deuterated analogue in an effort to improve the fundamental understanding of its vibrational spectra. Coupled with density functional theory (DFT) calculations, the first for this compound, and full spectral modeling, we generate the complete vibrational spectra of UFH and compare them to prior optical spectroscopic results. In particular, the combination of DFT with INS allows us to identify multiple distinct chemical environments in the water bending and OH stretching regions. Whereas the water molecules directly bound to the U atoms execute OH stretching around 3600 cm–1, a second class of H-bonded waters vibrate below 3000 cm–1, an indicator of strong H bonding. In addition, a class of librational water modes are observed between 400 and 900 cm–1, which themselves can be separated in energy according to their chemical environments. Measurements presented herein directly assist in the assignment of certain spectral features in the infrared spectrum and will inform future investigations of UFH for environmental or forensics purposes.

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Assessing hand-held Raman spectrometer FirstDefender RM for nuclear safeguards applications

Cited by 9 publications

References 14 publications

Elucidation of the Structure and Vibrational Spectroscopy of Synthetic Metaschoepite and Its Dehydration Product

Elucidation of the Structure and Vibrational Spectroscopy of Synthetic Metaschoepite and Its Dehydration Product

Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF₄(H₂O)_2.5

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Assessing hand-held Raman spectrometer FirstDefender RM for nuclear safeguards applications

Cited by 9 publications

References 14 publications

Elucidation of the Structure and Vibrational Spectroscopy of Synthetic Metaschoepite and Its Dehydration Product

Elucidation of the Structure and Vibrational Spectroscopy of Synthetic Metaschoepite and Its Dehydration Product

Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF4(H2O)2.5

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Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF₄(H₂O)_2.5