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At least 577 records · Page 32

A highly efficient uranium grabber derived from acrylic fiber for extracting uranium from seawater

Acrylic fiber can be chemically converted to an am- idoxime and carboxylate containing chelating adsorbent for extraction of uranium from seawater. At an optimized ratio of amidoxime:carboxylate, the chelating fiber in real seawater shows a higher uranium, shorter saturation time and lower vanadium adsorption capacity relative to similar high-surface area chelating fibers developed recently using a radiation-induced grafting method. This simple and low-cost synthesis method can be scaled up to mass produce the chelating fiber for recovering metals from aquatic environments including production of uranium from seawater.

Pan, H B.↗

Computationally efficient dielectric calculations of molecular crystals

The microscopic dielectric response is a key quantity for electronic materials such as organic semiconductors. Calculations of this response for molecular crystals are currently either expensive or rely on extreme simplifications such as multipole expansions which lack microscopic detail. We present an alternate approach using a microscopic analogue of the Clausius-Mossotti equation, which constructs the dielectric response of a crystal from an eigenvalue decomposition of the dielectric response of individual molecules. This method can potentially be used to examine the effects of defects, disorder, and surfaces on the dielectric properties of molecular solids.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Super-radiant plasmon mode is more efficient for SERS than the sub-radiant mode in highly packed 2D gold nanocube arrays

The field coupling in highly packed plasmonic nanoparticle arrays is not localized due to the energy transport via the sub-radiant plasmon modes, which is formed in addition to the regular super-radiant plasmon mode. Unlike the sub-radiant mode, the plasmon field of the super-radiant mode cannot extend over long distances since it decays radiatively with a shorter lifetime. The coupling of the plasmon fields of gold nanocubes (AuNCs) when organized into highly packed 2D arrays was examined experimentally. Multiple plasmon resonance optical peaks are observed for the AuNC arrays and are compared to those calculated using the discrete dipole approximation. The calculated electromagnetic plasmon fields of the arrays displayed high field intensity for the nanocubes located in the center of the arrays for the lower energy super-radiant mode, while the higher energy sub-radiant plasmon mode displayed high field intensity at the edges of the arrays. The Raman signal enhancement by the super-radiant plasmon mode was found to be one hundred fold greater than that by sub-radiant plasmon mode because the super-radiant mode has higher scattering and stronger plasmon field intensity relative to the sub-radiant mode.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗