INTRODUCTION I t is well known that elements exist in coal in a variety of different modes of occurrence [1,2]. Such modes can vary from the element being totally dispersed in the macerals (e.g. organic sulfur, carboxyl-bound Ca in lignite) to discrete mineral occurrences (e.g. pyrite, FeS,, quartz, SiO,, etc.). Recently, we showed that X-ray absorption fine structure (XAFS) spectroscopy is cap...

A new method of grazing incidence X-ray absorption spectroscopy using an off-specular reflection geometry referred to as Yoneda-XAFS is presented. Using an asymmetric setup, with the detector centered at the Yoneda peak, this technique is sensitive to lateral heterogeneities which typically occur at surfaces or interfaces. The Yoneda-XAFS technique was used for the ex situ investigation of a sp...

Micro-XAFS and chemical imaging techniques have been widely applied for studies of heterogeneously distributed systems, mostly in hard X-ray (>5 keV) or in soft X-ray (<1.5 keV) energies. The microprobe endstation of the SXRMB (soft X-ray microcharacterization beamline) at the Canadian Light Source is optimized at the medium energy (1.7-5 keV), and it has been recently commissioned and is avail...

We consider fundamental structures in x-ray absorption spectra over a wide energy range. We formulate the elastic scattering in addition to the photoelectric absorption in recently reported photon interference x-ray absorption fine structure (pXAFS). The simulations show excellent agreement with experimental x-ray absorption spectra for platinum and tungsten powders far above and below the L ab...

The local structure of several samples of BaTiO3 prepared by solution-gelation method with different particle sizes has been investigated using XAFS. Although the macroscopic crystal structure changes from tetragonal to cubic at room temperature when the particle size is smaller than 100 nm, Raman and XAFS spectroscopy measurements obtain that Ti atoms are displaced from the center of cubic sym...

Lifetime-broadening-suppressed (LBS) state-selective XAFS spectra can be deduced by analyzing resonant inelastic x-ray scattering (RIXS) in terms of formulae derived from the Kramers-Heisenberg equation. By a combination of third-generation synchrotron sources and spectrometers equipped with a large acceptance as well as high-resolution analyzers, high-quality RIXS data to extract LBS selective...

XAFS and μ-XAFS spectra were collected at the Cu K-edge for seven chrysocolla samples (Peru, USA, and Congo). The results suggest that that the local structure around Cu is similar to that in Cu(OH)2 (spertiniite). Cu-L3 STXM imaging and spectroscopy confirm that the chrysocolla samples examined here consist of mesoscopic Cu(II)-rich domains surrounded by Si-rich domains (in agreement with resu...

XAFS measurements at both the M,,, and L,, edges of Pt and Au as well as sca~~ring electron microscopy studies have been canied out for a series of porous silicon speci~nens onto which fine particles of Au and Pt with nanometre arid tens of nanometre dimensions have been dispersed. A wet chemistry technique developed in our laboratory was used for the deposition. The Au XAFS clearly show that t...

X-ray-absorption fine-structure ~XAFS! measurements have been carried out at the Pr L III and Os L III edges on the Pr-based heavy-fermion superconductor PrOs4Sb12 . The x-ray absorption near-edge structure results suggest that the Pr valence is very close to 31 with at most a small amount of Pr @vPr;3.019(3)# , while Os is close to metallic in this material. The extended XAFS results show that...

Quick-scanning X-ray absorption fine structure (XAFS) measurements were performed in transmission mode using a PILATUS 100K pixel array detector (PAD). The method can display a two-dimensional image for a large area of the order of a centimetre with a spatial resolution of 0.2 mm at each energy point in the XAFS spectrum. The time resolution of the quick-scanning method ranged from 10 s to 1 mi...