Chemical and spectroscopic characterization of plutonium tetrafluoride.

Anhydrous plutonium tetrafluoride is an important intermediate in the production of metallic Pu. This historically important compound is also known to exist in at least two distinct, yet understudied hydrate forms, PuF·HO(s) (0.5 ≤ ≤ 2) and PuF·2.

Laser-Induced Plasmas of Plutonium Dioxide in a Double-Walled Cell.

Plutonium research has been stifled by the significant number of administrative controls and safety procedures, space and instrumentation limitations in radiological gloveboxes, and the potential for personnel and equipment contamination. To address the limited number of spectroscopic studies in Pu-bearing compounds in the current scientific literature, this work presents the use of double-walled cells (DWCs) in "clean" buildings/laboratories as an alternative to research in radiological gloveboxes. This study reports the first laser-induced breakdown spectroscopy (LIBS) experiments of a PuO pellet contained within a DWC, where the formation of elemental (atomic and ionic) species as well as the evolution from elemental to molecular products (PuO) was measured.

Diffuse Reflectance Spectroscopy and Principal Component Analysis to Retrospectively Determine Production History of Plutonium Dioxide.

Diffuse reflectance spectroscopy measurements in the shortwave infrared (930-1600 nm) spectral region were acquired for Pu(CO)•9HO and its thermal decomposition product, PuO. We analyzed a total of eight PuO samples that were produced at different calcination temperatures (300, 350, 450, 525, 600, 675, 750, and 900 °C). Our goal was to identify spectroscopic fingerprints that could be used to gain retrospective information regarding the production parameters of these important nuclear compounds.

Probing the hydrolytic degradation of UF in humid air.

This manuscript describes the chemical transformations that occur during hydrolysis of uranium tetrafluoride (UF) due to its storage in humid air (85% and 50% relative humidity) at ambient temperatures. This hydrolysis was previously reported to proceed slowly or not at all (depending on the percent relative humidity); however, previous reports relied primarily on X-ray diffraction methods to probe uranium speciation. In our report, we employ a battery of physiochemical probing techniques to explore potential hydrolysis, including Raman spectroscopy, powder X-ray diffraction, F nuclear magnetic resonance spectroscopy, scanning electron microscopy, and focused ion beam microscopy with energy-dispersive X-ray spectroscopy.

Characterizing the solid hydrolysis product, UF(HO), generated from neat water reactions with UF at room temperature.

Uranium tetrafluoride (UF) is an important intermediate in the production of UF and uranium metal. Room temperature hydrolysis of UF was investigated using a combination of Fluorine-19 nuclear magnetic resonance spectroscopy (F NMR), Raman and infrared spectroscopy, powder X-ray diffraction, and microscopy measurements. UF(HO) was identified as the primary solid hydrolysis product when anhydrous UF was stirred in deionized water.

Dependence of surface-enhanced infrared absorption (SEIRA) enhancement and spectral quality on the choice of underlying substrate: a closer look at silver (Ag) films prepared by physical vapor deposition (PVD).

Silver (Ag) films of varying thickness were simultaneously deposited using physical vapor deposition (PVD) onto six infrared (IR) substrates (BaF(2), CaF(2), Ge, AMTIR, KRS-5, and ZnSe) in order to correlate the morphology of the deposited film with optimal SEIRA response and spectral band symmetry and quality. Significant differences were observed in the surface morphology of the deposited silver films, the degree of enhancement provided, and the spectral appearance of para-nitrobenzoic acid (PNBA) cast films for each silver-coated substrate. These differences were attributed to each substrate's chemical properties, which dictate the morphology of the Ag film and ultimately determine the spectral appearance of the adsorbed analyte and the magnitude of SEIRA enhancement.