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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.
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TL;DR: In this paper, the hydration of ions in aqueous solution was studied at room temperature by x-ray absorption spectroscopy and molecular dynamics simulation and no evidence of significant contributions from the second hydration shell to the EXAFS signal was found in the solutions.
Abstract: The hydration of ions in aqueous solutions was studied at room temperature by x-ray absorption spectroscopy and molecular dynamics (MD) simulation. The extended x-ray absorption fine structure (EXAFS) above the Zn K-edge was interpreted using the multiple-scattering approach by taking into account only one coordination shell composed of water molecules at R(Zn - O) = with a mean square relative displacement (MSRD) . No evidence of significant contributions from the second hydration shell to the EXAFS signal was found in the solutions. This is explained by the cancellation interference effect between double-scattering and single-scattering EXAFS signals in the second shell due to large thermal/static disorder as predicted by our MD simulation and by known results of diffraction techniques.
67 citations
TL;DR: In this paper, femtosecond time-resolved transmission spectroscopy was used to study the density and time dependence of transient absorption changes of CdSe nanocrystals.
Abstract: We use femtosecond time-resolved transmission spectroscopy to study the density and time dependence of transient absorption changes of CdSe nanocrystals. Our data show pronounced absorption saturation up to complete bleaching of the lowest optical transition. At high carrier density the nonlinear spectra show several peaks that can be related to the two lowest quantized electron states. Thetime dependence of the carrier-induced absorption changes indicates an ultrafast relaxation process within the strongly broadened absorption lines.
67 citations
TL;DR: In this article, the structural, electronic, and magnetic properties of chemically synthesized Sn1−xCoxO2 (x=000 to 005) nanoparticles were analyzed using X-ray diffraction and transmission electron microscope measurements.
Abstract: We present a detailed study on the structural, electronic, and magnetic properties of chemically synthesized Sn1−xCoxO2 (x=000 to 005) nanoparticles X-ray diffraction and transmission electron microscope measurements were performed to analyze the crystal structure and morphology of Sn1−xCoxO2 nanoparticles The energy dispersive x-ray analysis measurements were performed to check the possible presence of any impurity elements in the nanocrystals The near edge x-ray absorption fine structure (NEXAFS) experiments at Sn M5,4-edge and Co L3,2-edge were performed to probe the local environment of Sn and Co ions in the SnO2 matrix The NEXAFS at Co L3,2-edge, along with multiplet calculations, indicate that the Co is substituted at the Sn site in SnO2 matrix with +2 charge state and do not form metallic clusters and other oxide phases The ferromagnetic nature of these materials was confirmed by x-ray magnetic circular dichroism and room temperature magnetization hysteresis loop measurements
67 citations
TL;DR: In this paper, a combination of X-ray absorption near edge structure (XANES) and extended Xray absorption fine structure (EXAFS) spectroscopies, together with ab initio structure calculations, was used to explore the structure of the Cu in these reagents.
Abstract: The cyanocuprate reagents, prepared from CuCN + 7 equiv of organolithium, appear to possess both unique spectroscopic and unique reactivity properties in comparison with the analogous reagents prepared from CuX (X = Cl, Br, I). We have used a combination of X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopies, together with ab initio structure calculations, to explore the structure of the Cu in these reagents. The XANES measurements support earlier, preliminary EXAFS indications that cyanide is not coordinated to Cu in the so-called `higher-order` cuprate prepared from CuCN + 2BuLi. CuCN{center_dot}2LiCl exists in THF as an oligomer of ...Cu-C=N-Cu... units. The average Cu environment consists of two coordinated cyanides with the possible presence of a third ligand for some of the Cu sites. CuCN + BuLi and CuCN + 2BuLi both contain two-coordinate Cu, with average Cu-C bond lengths of 1.89 and 1.93 A, respectively. One cyanide remains coordinated to Cu in CuCN + BuLi, while both cyanides are displaced in CuCN + 2BuLi. Ab initio structure calculations are consistent with this picture, even to the extent of predicting the correct average Cu bond lengths. The theoretical calculations demonstrate that, in the most stablemore » structure, the cyanide is associated with the alkyl groups that are bound to the Cu. 76 refs., 6 figs., 1 tab.« less
67 citations
TL;DR: In this article, the electrostatic forces between benzene, naphthalene, and anthracene on the TiO2(110) surface were investigated using near edge x-ray absorption spectroscopy and thermal programmed desorption.
Abstract: The adsorption of benzene, naphthalene, and anthracene on the TiO2(110) surface has been investigated using near edge x-ray absorption spectroscopy (NEXAFS), x-ray photoelectron spectroscopy, and thermal programmed desorption. For all three adsorbates a planar adsorption geometry is found. In contrast to the bonding of benzene and larger acenes to metal surfaces, we find that the interaction is dominated by electrostatic forces between the adsorbed molecules and the TiO2(110) substrate. The fact that the average tilt angle between molecular and surface plane as determined by NEXAFS is substantially different from zero indicates the presence of defect species.
67 citations