Topic
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.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this paper, the optical data are explained in terms of the different oxidation states adopted by the chromium ions into the glass network and the absorption peak at ground state exciton energy, the absorption at band gap, and the free exciton binding energy are determined.
Abstract: Lithium aluminum silicate glass system (LAS) implanted with chromium ions is prepared. The reflectance and transmittance measurements are used to determine the dispersion of absorption coefficient. The optical data are explained in terms of the different oxidation states adopted by the chromium ions into the glass network. It is found that the oxidation state of the chromium depends on its concentration. Across a wide spectral range, 0.2–1.6μm, analysis of the fundamental absorption edge provides values for the average energy band gaps for allowed direct and indirect transitions. The optical absorption coefficient just below the absorption edge varies exponentially with photon energy indicating the presence of Urbach’s tail. Such tail is decreased with the increase of the chromium dopant. From the analysis of the optical absorption data, the absorption peak at ground state exciton energy, the absorption at band gap, and the free exciton binding energy are determined. The extinction coefficient data are us...
118 citations
[...]
TL;DR: In this paper, different kinds of absorption corrections are described and parameters for use in calculating the corrections are tabulated, as well as different types of absorption correction parameters for each of them.
Abstract: Of the processes that reduce the intensity of X-rays passing through matter, photoelectric absorption, scattering and extinction are important for the X-ray wavelengths used in crystallography. This chapter discusses each in turn. Different kinds of absorption corrections are described and parameters for use in calculating absorption corrections are tabulated.
118 citations
TL;DR: In this paper, the authors derived the values of absorption constant covering the range 1 cm−1 to 104 cm− 1 from transmission measurements made on singlecrystal gallium arsenide, where there is a knee beyond which the absorption increases relatively slowly with photon energy.
Abstract: Values of absorption constant covering the range 1 cm−1 to 104 cm−1 have been derived from transmission measurements made on single‐crystal gallium arsenide. The absorption edge is very steep up to ∼4000 cm−1, where there is a knee beyond which the absorption increases relatively slowly with photon energy. The energy bands have been calculated using Kane's theory. From these a theoretical absorption curve has been obtained which shows very good agreement with the experimental data.Using semi‐insulating material, it has been possible to measure the shift of the edge with applied electric field. The effect is small (∼200‐μ ev shift for 5000‐v/cm field) but is in good agreement with theory.
118 citations
TL;DR: In this paper, Ni(OH) 2 en phases α and β, a temperature ambiante and a temperature de l'azote liquide, a comparison of longueurs des liaisons.
Abstract: Etude de Ni(OH) 2 en phases α et β, a la temperature ambiante et a la temperature de l'azote liquide. Comparaison des longueurs des liaisons
118 citations
TL;DR: In this article, the evolution of the local structure around ferric ions has been followed through X-ray Absorption Spectroscopy (XAS) during the formation of hematite from ferric gels at 92°C.
118 citations