Grazing incidence X-ray diffraction GIXD

Two-dimensional (2-D) crystallites are generally of a lower symmetry than 3-D crystals. The molecules in the 2-D crystallites cannot pack across a center of inversion as they most commonly do in 3-D. By applying modern analytical tools such as scanning tunneling and probe microscopy (STM, SPM), transmission electron microscopy (TEM), grazing incidence X-ray diffraction (GIXD), electrospray ionization (ESI) and matrix-assisted laser-... 

FIGURE 3.8 Grazing incidence x-ray diffraction (GIXD) pattern of a thin carbyne deposit. D = diamond substrate. 

Section 4.1 Grazing Incidence X-Ray Diffraction (GIXD) Tae Joo Shin and Hoichang Yang... 

The present work is concerned with the influence of the pretreatment of an alumina-aerogel supported Pd catalyst on its activity in propane oxidation. The state of Pd and the crystalline state of alumina aerogel were investigated by grazing-incidence X-ray diffraction (GIXD). To our knowledge, this method is applied for the first time to supported metal catalysts. In addition, a comparison of the structural and catalytic oxidation properties of Pd, Pt and Pt-Rh supported on alumina carriers was made. 

Unique information about the unit cell in quasi-crystaUine monolayers can be obtained from X-ray °, neutron , heUum or low energy electron diffraction (LEED) data. In the grazing incidence X-ray diffraction (GIXD) experiment the beam is directed at the coated surface at a low angle and experiences total internal reflection from the metal support underneath the monolayer. The analysis of reflectivity and diffraction pattern of this reflected beam provides information about the molecular structure of the crystalline films, the thickness and refractive index of the layers and the roughness of the surface s . These experiments, however, require sophisticated and expensive equipment and are not therefore used routinely for monolayer characterization. 

The dispersion of palladiiim was measured by CO chemisorption, following the procediare described earlier [5]. The state of palladium and the structure of supports were investigated, in some cases, by grazing-incidence X-ray diffraction (GIXD) as previously reported [6]. 

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