Reactions of Laser-Ablated Uranium Atoms with H₂O in Excess Argon:  A Matrix Infrared and Relativistic DFT Investigation of Uranium Oxyhydrides

Abstract

Laser-ablated U atoms react with H2O during condensation in excess argon. Infrared absorptions at 1416.3, 1377.1, and 859.4 cm(-1) are assigned to symmetric H-U-H, antisymmetric H-U-H, and U=O stretching vibrations of the primary reaction product H(2)UO. Uranium monoxide, UO, also formed in the reaction, inserts into H2O to produce HUO(OH), which absorbs at 1370.5, 834.3, and 575.7 cm(-1). The HUO(OH) uranium(IV) product undergoes ultraviolet photoisomerization to a more stable H2UO2 uranium(VI) molecule, which absorbs at 1406.4 and 885.9 cm(-1). Several of these species, particularly H2UO2, appear to form weak Ar-coordinated complexes. The predicted vibrational frequencies, relative absorption intensities, and isotopic shifts from relativistic DFT calculations are in good agreement with observed spectra, which further supports the identification of novel uranium oxyhydrides from matrix infrared spectra.

Environmental modeling of uranium interstitial compositions of non-stoichiometric oxides: experimental and theoretical analysis

“…Notwithstanding that our continues research interest for methodological MS developments and analytical implementation has been focused on elaboration of analytical protocols for environmental assessment mainly of organic contaminations, foodstuffs monitoring, and drugs of abuse analysis (Sukul et al 2010;Kusari et al 2009;Banerjee et al 2006;Smejkalova et al 2006;Frimmel et al 2002;Choi et al 2012;Spiteller 2012a, b, c, 2014;Lamshoeft et al 2011;Spiteller 1985Spiteller , 1987Spiteller , 2012Spiteller and Saiz-Jimenez 1990), the herein presented study is focused on uranium speciation in gas and condense phase, utilizing mass spectrometry and vibrational spectroscopy. Nevertheless of the generally higher method detection limits of the vibrational spectroscopic methods, the characteristic vibrational profile [ 970-900 cm -1 of m O=U=O as (m 3 ) stretching vibration (Best et al 1988;Guimbretiere et al 2012;Liang et al 2005;Mueller et al 2009;He et al 2002;Ivanova and Spiteller 2014) enable the utilization of the method for quantitative purposes. The full method validation applicable to real environmental problematic.…”

Water Adsorption on Platinum Dioxide and Dioxygen Complex: Matrix Isolation Infrared Spectroscopic and Theoretical Study of Three PtO2–H2O Complexes

“…Accordingly, we assign the group C absorptions to the PtO 2 -H 2 O complex. The similarity in the H 2 16 O/ H 2 18 O isotopic frequency ratios for isomers C (1.0037 and 1.0021 for the antisymmetric and symmetric HÀOÀH vibrations) and B suggested that the coordination fashion of water to the platinum center was preserved in spite of the breaking of OÀO bond during the conversion from B to C.…”

How Can Uranium Ions (U+, U2+) Activate the OH Bond of Water in the Gas Phase?

“…unique ability to activate notoriously unreactive molecules such as CH 4 and CO 2 . [2] In addition, there is an increasing interest in studying the gas-phase chemistry of actinides in order to obtain a better understanding of the particular character of the electronic structures and energetics of the early actinides, and especially the direct and indirect roles of the 5f electrons in their chemistry.…”

“…[3] Moreover, the chemistry of uranium, particularly the hydrolysis reaction, is of fundamental importance. [4] In a recent experimental study, [5] the pathways and rate constants of the reaction of gas-phase uranium cations with H 2 O were investigated using a quadrupole ion-trap mass spectrometer (QIT-MS). In the case of the reaction between U + and H 2 O the reaction products shown in Equations (1) and (2) were detected.…”