XANES

About: XANES is a research topic. Over the lifetime, 7737 publications have been published within this topic receiving 188032 citations.

Structural and electronic properties of protein/thiolate-protected gold nanocluster with “staple” motif: A XAS, L-DOS, and XPS study

Abstract: Following the recent breakthrough of total structural determination of a Au-thiolate nanocluster [P. Jadzinsky et al., Science 318, 430 (2007)], extensive interests have been stimulated to unveil (or revisit) the structure-property relationship of various thiolate-Au nanostructures in light of the new finding of –SR–(Au–SR)x– “staple” motif. Here, we present experimental x-ray absorption spectroscopy (XAS) and x-ray photoelectron spectroscopy (XPS) results on the local structure and electronic properties of thiolate-protected Au nanocluster encapsulated in bovine serum albumin (Au-BSA) together with theoretical calculation of projected local density of states (l-DOS) of Au25(SR)18 model cluster. Analysis of the Au L3-edge extended x-ray absorption fine structure (EXAFS) of Au-BSA suggested that the nanocluster is Au25 with Au-thiolate “staple” motif. X-ray absorption near-edge structure (XANES) and Au 4f XPS were used to probe the electronic behavior of Au-BSA. The Au d-electron density of Au-BSA was foun...

Sulfur X-ray absorption and vibrational spectroscopic study of sulfur dioxide, sulfite, and sulfonate solutions and of the substituted sulfonate ions X3CSO3- (X = H, Cl, F)

Abstract: Sulfur K-edge X-ray absorption near-edge structure (XANES) spectra have been recorded and the S(1s) electron excitations evaluated by means of density functional theory−transition potential (DFT−TP ...

In situ investigations of a Li-rich Mn–Ni layered oxide for Li-ion batteries

Abstract: A Li-rich layered oxide with the formula Li[Li0.2Mn0.61Ni0.18Mg0.01]O2 was successfully synthesised and characterised using several in situ characterisation techniques. The electronic state and structural evolution of the material upon cycling were investigated using in situ XRD, EXAFS and XANES measurements. XANES and SQUID magnetic measurements showed that the initial material contains a certain amount of Mn3+ in a low spin configuration (average Mn oxidation state: +3.75). In situ measurements showed that the first part of the charge (up to 4.4 V vs. Li+/Li) corresponds to oxidation of the Mn3+ fraction, and that the oxidation of nickel occurs only later, on the main charge plateau at 4.5 V. Electrochemical and structural results tend to show that the main first-charge plateau is a two-phase process where a new phase is created. This new phase is structurally very close to the starting one, and could be an oxygen-deficient spinel with a = 8.25 A. This process is non-reversible, and further cycling occurs in the new phase formed in situ.

The structure and reactivity of chemisorbed aromatics: Spectroscopic studies of benzene on Mo(110)

Abstract: The reactions of benzene on Mo(110) have been investigated under ultrahigh vacuum conditions using temperature programmed reaction spectroscopy (TPRS), x‐ray photoelectron spectroscopy (XPS), and near‐edge x‐ray absorption fine structure (NEXAFS) measurements. Benzene undergoes competing decomposition and desorption processes during temperature programmed reaction; saturation exposures of C6H6 made at a crystal temperature of 120 K yield a small amount of benzene desorption at 360 K as well as substantial H2 evolution at 400 and 530 K. Additionally, a trio of molecular benzene desorptions attributed to weakly bound and multilayer states is observed below 200 K. Isotopic exchange experiments demonstrate that the 360 K molecular desorption arises from intact chemisorbed benzene. For surface temperatures up to 300 K, carbon 1s photoelectron spectra show only a single photoemission peak at a binding energy of 284.0 eV, attributed to molecular benzene. Above 300 K, increasing amounts of atomic carbon are obser...