Showing 61 - 75 of 19584

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...

Electrolyte solutions in alkaline nuclear waste contain aluminate, hydroxide, nitrate and nitrite with sodium as the predominant counterion. The salts of these ions are highly soluble, so the liquids are highly concentrated. This study found that there is a substantial incompatibility between the...

The recently developed real-time nuclear–electronic orbital (RT-NEO) approach provides an elegant framework for treating electrons and selected nuclei, typically protons, quantum mechanically in nonequilibrium dynamical processes. However, the RT-NEO approach neglects the motion of the other nuclei...

The molecular speciation of aluminum (Al3+) in alkaline solutions is fundamental to its precipitation chemistry within a number of industrial applications that include ore refinement and industrial processing of Al wastes. Under these conditions, Al3+ is predominantly Al(OH)4–, while at high [Al3+]...

X-ray, energetic photon, and electron irradiation can ionize and electronically excite target atoms and molecules. These excitations undergo complicated relaxation and energy-transfer processes that ultimately determine the manifold system responses to the deposited excess energy. In weakly bound...

The radiolysis of liquid water and the radiation-matter interactions that happen in aqueous environments are important to the elds of chemistry, materials, and environmental sciences, as well as biological and physiological response to extreme conditions and medical treatments. The initial stage of...

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...

Understanding, controlling, and preventing aggregation of suspended particles is of fundamental importance in a number of scientific and industrial fields. There are several methods for analyzing aggregate morphology and aggregation kinetics, but small-angle scattering (SAS) techniques provide...

The iron oxy-hydroxide lepidocrocite (𝛾γ-FeOOH) is an abundant mineral critical to a number of chemical and technological applications. Of particular interest are the ground state and finite temperature magnetic order and the subsequent impact this has upon crystal properties. The magnetic...

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...

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...

Real-time electronic structure methods provide an unprecedented view of electron dynamics and ultrafast spectroscopy on the atto- and femtosecond time scale with vast potential to yield new insights into the electronic behavior of molecules and materials. In this Review, we discuss the fundamental...

Silica-encapsulated gold core@shell nanoparticles (Au@SiO2 CSNPs) were synthesized via a tunable bottom-up procedure to catalyze the aerobic oxidation of benzyl alcohol. The nanoparticles exhibit a mesoporous shell which enhances selectivity by inhibiting the formation of larger species. Adding...

The accurate description of excited vibronic states is important for modeling a wide range of photoinduced processes. The nuclear–electronic orbital (NEO) approach, which treats specified protons on the same level as the electrons, can describe excited electronic–protonic states. Herein the...

Nitrite (NO2−) is a prevalent nitrogen oxyanion in environmental and industrial processes, but its behavior in solution, including ion pair formation, is complex. This solution phase complexity impacts industries such as nuclear waste treatment, where NO2− significantly affects the solubility of...