Surfaces X-ray scattering

Toney M F, Floward J N, Richter J, Borges G L, Gordon J G, Meiroy O R, Wiesier D G, Yee D and Sorensen L B 1995 Distribution of water moiecuies at Ag(111 )/eiectroiyte interface studied with surface x-ray scattering Surf. Sc/. 335 326-32... 

Ocko B M, Wang X J, Adzic R and Wandiowski Th 1998 Surface x-ray scattering studies of Eiectrosorption Synchrotron Radiat. News 11 23-30... 

Ocko B M, Magnussen O M, Wang J, Adzic R R, Shi Z and Lipkowski J 1994 A criticai comparison of eiectrochemicai and surface x-ray scattering resuits at the Au(111) eiectrode in KBr soiutions Electroanal. Chem. 376 35-9... 

Nagy, Z., and H. Yon, Applications of surface X-ray scattering to electrochemistry problems, Electrochim. Acta, 47, 3037 (2002). 

Wu S, Lipkowski J, Magnussen OM, Ocko BM, Wandlowski T. 1998. The driving force for (p X - 3) <->(1x1) phase transition of Au(lll) in the presence of organic adsorption A combined chronocoulometric and surface X-ray scattering study. J Electroanal Chem 446 67-77. 

Tolmachev Y V, Menzel A, Tkachuk AV, Chu YS, You H. 2004. In situ surface X-ray scattering observation of long-range ordered ( /T9 x yi9)R23.4°-13CO structure on Pt(lll) in aqueous electrolytes. Electrochem Solid-State Lett 7 E23-E26. 

Gallagher ME, Blizanac BB, Lucas CA, et al. 2005. Structure sensitivity of CO oxidation on gold single crystal surfaces in alkaline solution Surface X-ray scattering and rotating disk measurements. Surf Sci 582 215-226. 

Surface Enhanced Raman Spectroscopy (SERS), 176, 184, 194 Surface X-Ray Scattering (SXS), 247-248... 

Synchotron based techniques, such as surface X-ray scattering (SXS) and X-ray absorption spectroscopy (XAS), have found increased use in characterization of electrocatalysts during electrochemical reactions.37 These techniques, which can be used for characterization of surface structures, require intricate cell designs that can provide realistic electrochemical conditions while acquiring spectra. Several examples of the use of XAS and EXAFS in non-precious metal cathode catalysts can be found in the literature.38 2... 

A detailed electrochemical study of Ni(l 11) electrodes in H2SO4 solution in conjunction with in situ scanning tunneling microscopy (STM) and in situ surface X-ray scattering methods (SXS, x-ray diffraction and x-ray reflectivity) was carried out by Scherer et al. [18]. 

Bromide adsorption on Au(lll) has also been studied, applying in situ surface X-ray scattering (SXS) and STM [56]. The potential-dependent adlayer density agreed well with the earlier pubKshed bromide surface excess densities, obtained in electrochemical measurements. At very positive potentials, a bromide-induced step-flow etching of Au occurred. 

J. X. Wang, R. P. Adzic, B. M. Ocko, In situ surface X-ray scattering studies of electrosorption in Interfacial Electrochemistry. Theory, Experiment and Applications (Ed. A. Wifckowski), Marcel Dekker, New York-Basel, 1999, p. 175. 

Among the most common surface X-ray scattering techniques used to probe mineral-fluid interface structure is the measurement of crystal truncation rods (CTRs). CTRs are diffuse streaks of intensity connecting bulk reciprocal lattice (Bragg) points in the direction perpendicular to a surface, and arise as a natural... 

The study by TC with the surface X-ray scattering also suggested that at high electric fields the density of the water next to the metal surface is unexpectedly high. At a equal to —10 and + 25 juC/cm2, the ratios of the estimated density in the inner layer to that expected from the bulk density of water were 1.3 and 2.3, respectively. 

Atomic Structure of Oxide Surfaces by Surface X-ray Scattering... 

Fig. 13 Structural models used to analyze the XPD scans shown in Fig. 13. These include the optimized, reconstructed A-type surface (a), the optimized, reconstructed B-type surface (b), a preliminary model from an unpublished surface x-ray scattering experiment on bulk Fe304(001) (c), and the structure predicted by a molecular dynamics calculation (d).

STM is one of only a few techniques that can be used to obtain detailed structural information at the solid/liquid interface. Surface x-ray scattering (SXS) can be used and probes the local order of the surface with higher resolution than STM, but the information is averaged over an extended area of the surface. STM has the advantage that it can image lighter atoms that do not scatter x-rays well, but it is fairly insensitive for distinguishing between atomic or molecular species. Thus, as usual, a combination of the two techniques can provide a more detailed description of the solid-liquid interface. 

Fortunately, the success of surface science, optical and x-ray techniques in the last few decades has provided access for electrochemists to structural information of electrode/electrolyte interfaces. The optical and X-ray spectroscopic techniques have mainly been used in situ, i.e., in the presence of the bulk electrolyte. These techniques include EXAFS (extended x-ray absorption fine structure), SXS (surface x-ray scattering), XSff (x-ray standing wave technique, SERS (surface enhanced Raman scattering), NOM (nonlinear optical methods) IRS (infrared spectroscopy), MS (Mossbauer spectroscopy), RLS (radioactive labelling spectroscopy), STM (scanning tunneling microscopy), and... 

X-ray methods provide an important route to determining interfacial structure when the metal electrode is a single crystal [13, 14]. One technique, namely, extended X-ray absorption fine structure, or EXAFS, depends on the absorption of X-rays by the atoms in the interfacial region. The other method is surface X-ray scattering or surface X-ray diffraction. Both methods require intense X-ray sources and therefore can only be carried out at a particle accelerator or synchrotron. The discussion here is limited to scattering experiments. 

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