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Journal ArticleDOI

Defects on surfaces

01 Mar 1988-Bulletin of Materials Science (Springer India)-Vol. 10, Iss: 1, pp 161-172
TL;DR: A brief review of various types of defects on surfaces and their role in surface reactions is presented in this article, with particular emphasis on defects like steps/kinks and additives (promoters and poison).
Abstract: A brief review of various types of defects on surfaces and their role in surface reactions is presented. Particular emphasis is given on defects like steps/kinks and additives (promoters and poison).
Citations
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Journal ArticleDOI
TL;DR: In this paper, a density functional theory study has been carried out to investigate the hydration kinetics of periclase (MgO) through the interaction between water and pericloase (0, 0, 1) and (1, 1, 1), 1) surfaces.

4 citations

References
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Journal ArticleDOI
TL;DR: In this article, thermal He scattering from CO/Pt(111) at low coverages (θCO < 0.01) was shown to be dominated by long-range attractive forces centered at the adsorbed CO molecules.

41 citations

Journal ArticleDOI
24 Apr 1987-Science
TL;DR: This approach has demonstrated that metal single crystals can be used to successfully model many important catalytic reactions and has established a direct link between the results of ultrahigh vacuum surface measurements and the chemistry that occurs under typical catalytic-processing conditions.
Abstract: One-sixth of the value of all goods manufactured in the United States involves catalytic processes. However, in spite of this dramatic economic impact, little is known about this broad subject at the molecular level. In the last two decades a variety of techniques have been developed for studying at the atomic level the structure, composition, and chemical bonding at surfaces. These techniques have been used to study adsorption and reaction on metal single crystals in an ultrahigh vacuum environment or to analyze catalysts before and after reaction. An important new development has been the coupling of an apparatus for the measurement of reaction kinetics at elevated pressures with an ultrahigh vacuum system for surface analysis. This approach has demonstrated that metal single crystals can be used to successfully model many important catalytic reactions and has established a direct link between the results of ultrahigh vacuum surface measurements and the chemistry that occurs under typical catalytic-processing conditions.

39 citations

Journal ArticleDOI
TL;DR: In this paper, a low-energy electron-diffraction analysis of the atomic structure of the surface of body-centered-cubic iron was performed and damped relaxations from bulk-like structure were found in the directions both parallel and perpendicular to the surface and extending four layers deep into the lattice.
Abstract: We report the results of a low-energy electron-diffraction analysis of the atomic structure of the {310} surface of body-centered-cubic iron. Damped relaxations from bulklike structure are found in the directions both parallel and perpendicular to the surface and extending four layers deep into the lattice. The surface structure is as follows: first interlayer spacing ${d}_{12}=0.76\ifmmode\pm\else\textpm\fi{}0.03$ \AA{} (bulk value is 0.906 \AA{}), second interlayer spacing ${d}_{23}=1.02\ifmmode\pm\else\textpm\fi{}0.03$ \AA{}, third interlayer spacing ${d}_{34}=0.87\ifmmode\pm\else\textpm\fi{}0.04$ \AA{}, change of first-to-second layer registry shift $\ensuremath{\Delta}{a}_{12}=0.13\ifmmode\pm\else\textpm\fi{}0.05$ \AA{}, and change of second-to-third layer registry shift $\ensuremath{\Delta}{a}_{23}=0.03\ifmmode\pm\else\textpm\fi{}0.05$ \AA{}. Both changes of registry shifts are in the same direction, along a $〈310〉$ axis, and cause a decrease in the difference between nearest- and next-nearest-neighbor distances between atoms in adjacent layers.

29 citations

Journal ArticleDOI
TL;DR: The catalytic activity of surface step sites was probed by the thermal decomposition of ethylene and it clearly showed that the decomposition proceeds from terrace edges.
Abstract: Structural differences between a clean, reconstructed Pt(100) surface and one exhibiting chemical or structural irregularities have been identified by means of a scanning tunneling microscope. The (temperature-dependent) defect structure of a surface which had undergone a phase transition involving mass transport was characterized and compared to results obtained using other techniques. The catalytic activity of surface step sites was probed by the thermal decomposition of ethylene. The resulting surface roughening and buildup of carbon, which could be resolved in STM images, clearly showed that the decomposition proceeds from terrace edges.

27 citations