Vibrational properties of uranium fluorides

Characterizing the solid hydrolysis product, UF4(H2O)2.5, generated from neat water reactions with UF4 at room temperature

“…intensity, and Raman activity, as was recently done by Miskowiec et al for UFx with x = 3, 4, 4.5, and 5 29. …”

“…27,28 Furthermore, computational modeling to compliment modern physiochemical measurements might create new ways of understanding UF4 and other important nuclear materials that have not been studied using modern techniques. 29,30 The aforementioned UF4 work by Zhong et al in 2015 signified a potential paradigm shift with regards to UF4-water interactions at room temperature since UF4 was historically believed to be very stable under ambient environmental conditions. As such, it provided us with motivation to evaluate UF4-water interactions at room temperature using several modern analytical tools.…”

“…Raman spectroscopy is a particularly useful characterization tool for evaluating UF4 and the first high-resolution Raman spectrum of UF4 was published only five years ago by our group at the Savannah River National Laboratory. 31 Symmetry analysis of UF4 shows that over 42 optical modes should be Raman active, 29 and the published spectra show that many of those modes are measurable. In hindsight, previous Raman spectroscopic characterization attempts of UF4 were complicated due to significant fluorescence at typical interrogating wavelengths (632 and 647 nm) and an overall weak UF4 Raman signal intensity.…”

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

“…Electronic structure modeling has been extremely useful in understanding the vibrational spectra of nuclear materials, especially for modeling INS data. − Despite significant difficulties with open f-shell systems, density functional theory (DFT) has demonstrated success with regard to predicting the vibrational properties of actinides. − Most relevant to the present work is the combined theoretical and experimental investigation of uranyl fluoride hydrate with INS and DFT by Miskowiec et al In that work, the authors used DFT to predict the phonon spectrum of anhydrous UO 2 F 2 with intercalated waters. By directly predicting the measured dynamic structure factor, they established specific inferences about the coupling of water to certain vibrational modes.…”

Vibrational spectroscopy of uranium tetrafluoride hydrates

“…In fact, subsequent symmetry analysis of UF4 by Miskowiec et al has determined that as many as 42 vibrational modes should be active in UF4 due to its complex polymeric structure. 13 Despite these advancements, little has been done to apply similar vibrational spectroscopy techniques towards the study of the hydrated analogs of UF4, although application of these techniques can help elucidate the location of water molecules in the crystal lattice, which might help reveal more about the complex UF4 structure. For example, band frequencies and full-width at half-maximum (FWHM) values of the water OH stretch bands can be used as a probe to indicate the type of hydrogen bonding or the presence of free OH functional groups in the crystal lattice.…”