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The x-ray standing waves generated by dynamical Bragg diffraction were used to directly measure lattice locations of trace elements within and at the surface of a mineral single crystal. These high-precision measurements were made on natural Iceland spar calcite cleaved along the (1014) plane and reacted with a dilute aqueous lead solution. Within the bulk(More)
An x-ray-diffraction method that directly senses the phase of the structure factor is demonstrated and used for determining the local polarity of thin ferroelectric films. This method is based on the excitation of an x-ray standing-wave field inside the film as a result of the interference between the strong incident x-ray wave and the weak kinematically(More)
The atomic-scale structure of Zn2+ incorporated at the CaCO 3 (101 :4) surface by adsorption from solution was determined by X-ray standing wave triangulation and surface extended X-ray absorption fine structure spectroscopy. At low coverage (approximately 0.1 ML), Zn2+ substitutes for Ca2+ in the surface layer. Structural relaxation of the adjacent(More)
The adsorption of selenite ions (SeO~-) from a dilute aqueous solution onto a freshly-cleaved calcite (1014) surface was studied with the X-ray standing wave (XSW) technique. The complex ion SeO z-is found to selectively adsorb at the CO~ site via ionic exchange, forming a two-dimensional solid-solution of the form Ca(SeO3)x(CO3) 1 x at the interface. The(More)
By combining synchrotron X-ray standing wave (XSW) measurements with synchrotron X-ray reflectivity measurements, we have determined: (1) the precise three-dimensional location within the calcite unit cell of submonolayer Pb ions adsorbed at the calcite (104) surface from dilute aqueous solutions, and (2) the precise one-dimensional location of these unit(More)
We have instrumented the 5ID-C hutch of DND-CAT at the Advanced Photon Source (APS) for x-ray surface spectroscopy and scattering. A wide variety of experiments have already been carried out at 5ID-C, including studies on semiconductors, oxides, metals, nanodots, and biomolecular adsorption. We describe the beamline optics, data collection hardware and(More)
The surface structures of the (6 x 2), c(8 x 4) and (5 × 1) phases of Sn/Si(001) were studied using the X-ray standing wave technique. Using the (004) and (022) Bragg reflections, we find that the (6 x 2) and c(8 × 4) phases are composed of highly buckled Sn-Sn ad-dimers located 1.58 i above the bulk-like Si(004) surface atomic plane. The Sn atoms occupy(More)
This contribution reports the first X-ray standing wave structural characterization of self-assembled NLO-active chromophoric multilayers (SAMs). These siloxane-based self-assembled stilbazolium multilayers are intrinsically acentric and exhibit very large second-order nonlinear optical responses. The locations of bromide ions within the SAMs were precisely(More)
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