Extended X-ray absorption fine structure

About: Extended X-ray absorption fine structure is a research topic. Over the lifetime, 10452 publications have been published within this topic receiving 276744 citations.

Origin of the Red Color of Satsuma Copper-Ruby Glass as Determined by EXAFS and Optical Absorption Spectroscopy

Abstract: The origin of the ruby color of Satsuma glass, a famous copper-ruby glass produced in Japan in the mid-19th century, has been examined by electron microprobe analysis (EPMA), X-ray absorption fine structure (XAFS), and optical absorption spectroscopy analyses CuK XAFS analysis reveals that the major component of copper in the ruby glass consists of Cu(I) ions in the glass structure This species is distinct from Cu2O (cuprite), which we conclude is not responsible for the ruby color Optical absorption spectra measured at 300 and 77 K clearly distinguishes the absorptions due to the colloidal particles of metallic copper and Cu2O It is concluded that the trace amount of copper in the ruby glass, which is below the detection limit of the EPMA and XAFS techniques, exists as metallic copper particles of nanometer size and is responsible for the ruby-red appearance of the Satsuma glass

Site-selective EXAFS in mixed-valence compounds using high-resolution fluorescence detection: a study of iron in Prussian Blue.

Abstract: A quantitative analysis is presented for the site-selective Fe K-edge absorption spectra of Prussian Blue: Fe4[Fe(CN)6]3‚xH2 O( x ) 14-16). The site-selective spectra were recorded using high-resolution fluorescence detection of the K‚ emission from a polycrystalline sample. The K‚ fluorescence lines arising from the high-spin and lowspin sites are shifted in energy. Since the emission features partially overlap, fluorescence-detected absorption spectra using different emission energies represent different linear combinations of the pure high-spin and low-spin EXAFS. A numerical method was used to extract the individual site EXAFS spectra from the experimental data. The analysis yields a range of solutions. A unique solution can be obtained if homovalent model compounds are used to simulate the K‚ fluorescence emission from the two Fe sites in Prussian Blue. EXAFS analysis of the range of spectra obtained in the numerical method yields almost identical interatomic distances for the different spectra while the Debye-Waller factors vary considerably. The distances obtained in the EXAFS fit correspond to the crystallographic distances.

Synthesis and characterization of the Keggin-type ruthenium-nitrido derivative [PW11O39{RuN}]4- and evidence of its electrophilic reactivity.

Abstract: The ruthenium-nitrido POM derivative [PW11O39{RuVIN}]4- has been synthesized by reaction between [PW11O39]7- and [RuVINCl5]2- or [RuVINCl4]-. Its molecular structure has been confirmed from multinuclear 31P and 183W NMR spectroscopy together with an EXAFS study, while the oxidation state of the ruthenium bearing the nitrido ligand has been inferred both from 183W NMR and XANES analysis at the Ru-K edge. The potential of [PW11O39{RuVIN}]4- in N-atom transfer reactions has been demonstrated through reaction with triphenylphosphine, which ultimately leads to the release of the bis(triphenylphosphane)iminium cation [PPh3NPPh3]+ through several intermediates, among which the phosphoraniminato derivative [PW11O39{RuVNPh3}]3- has been structurally characterized. Its unusual oxidation state is in accordance with its EPR spectrum.