Predicting accurate nuclear magnetic resonance chemical shieldings relies upon cancellation of different types of errors between the theoretically calculated shielding constant of the analyte of interest and the reference. Often, the intrinsic error in computed shieldings due to basis sets...
The quantum mechanical treatment of both electrons and nuclei is crucial in nonadiabatic dynamical processes such as proton-coupled electron transfer. The nuclear−electronic orbital (NEO) method provides an elegant framework for including nuclear quantum effects beyond the Born–Oppenheimer...
Crystallization of Al3+-bearing solid phases from highly alkaline Na2O:Al2O3:H2O solutions commonly necessitates an Al3+ coordination change from tetrahedral to octahedral, but intermediate coordination states are often difficult to isolate. Here, a similar Al3+ coordination change process is...
Understanding mechanistic pathways to radiolytic hydrogen generation by metal oxyhydroxide nanomaterials is challenging because of the difficulties of distinguishing key locations of OH bond scission, from structural interiors to hydroxylated surfaces to physi-sorbed water molecules. Here we...
The stability of aluminum oxyhydroxide (AlOOH, boehmite) to radiolysis and dehydration to alumina (γ-Al2O3) under vacuum was investigated using TGA followed by detailed, structural analysis with Raman, powder X-Ray Diffraction (pXRD), high energy X-Ray Diffraction (heXRD), 27Al Magic Angle Spinning...
In highly alkaline “water-in-salt” Na2O/Al2O3/H2O solutions where the monomeric Al(OH)4– anion dominates, isolation of transitional species that seed crystallization of sodium aluminate salt hydrates has been challenging. For example, discrimination of dimeric [for example, Al2O(OH)62–] species via...
The incorporation of relatively minor impurity metals onto metal (oxy)hydroxides can strongly impact solubility. In complex highly alkaline multicomponent radioactive tank wastes such as those at the Hanford Nuclear Reservation, tests indicate that the surface area-normalized dissolution rate of...
Tetrahedrally coordinated aluminate Al(OH)4- and dialuminate Al2O(OH)62- anions are considered to be major species in aluminum-rich alkaline solutions. However, their relative abundance remains difficult to spectroscopically quantify due local structure similarities and poorly understood effects...
The role of oligomeric aluminate species in the precipitation of aluminum (Al) phases such as gibbsite (α-Al(OH)3) from aqueous hydroxide solutions remains unclear and difficult to probe directly, despite its importance for developing accurate predictions of Al solubility in highly alkaline systems...
Determining kinetic parameters such as activation energy (Ea), pre-exponential factor (A), rate constants, and reaction order (n) via thermal analysis techniques is important to material synthesis and fabrication, industrial production, biomedicals, energy storage, catalysis, etc. Various kinetic...
Understanding the reactivity behavior of aluminum oxyhydroxide phases, widely present in nuclear waste tanks, in radiation environments is essential to develop better nuclear waste processing approaches. Recent experiments using vibrational sum frequency generation, a surface sensitive technique...
