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Edward H. Conrad

Bio: Edward H. Conrad is an academic researcher from University of Missouri. The author has contributed to research in topics: Topological defect & Surface science. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.

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TL;DR: A review of surface defect formation on metal surfaces can be found in this paper, where the authors outline both the theoretical and experimental work on surface defect forming on metal systems, including surface roughening, faceting, and surface melting.
Abstract: The study of defect formation at metal surfaces is a fundamental problem in surface physics. An understanding of defect formation is pertinent to growth and diffusion mechanisms. In addition, surface roughening, faceting, and surface melting are all defect mediated phase transitions involving the formation of different topological defects. While the importance of defects at surfaces is well recognized, the study of surface defects has been hampered by the lack of sufficiently accurate experimental techniques. In fact, it is only in the past 6 years that experiments on the thermal generation of defects on metal surfaces have been performed. This review attempts to outline both the theoretical and experimental work on surface defect formation on metal systems.

4 citations


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TL;DR: In this paper, a new procedure for measuring wetting angles on nanoscale particles using surface melting is proposed, which is highly dependent on the geometry of a particle so it can be used as a measure.

12 citations

Journal ArticleDOI
TL;DR: In this paper, density functional theory (DFT) calculations were carried out on hydroxylated and solvated (H&S) Fe substrates and it was shown that these spherical Fe aggregates, formed mainly by (111) faces and with an important percentage of low-coordination sites, are excellent adsorbent substrates of H3AsO3 and should be considered as a reference to search for new supported catalysts.
Abstract: Density functional theory (DFT) calculations were carried out on hydroxylated and solvated (H&S) Fe substrates. Fe (110) and (111) extended surfaces as well as clusters of 32 and 59 atoms, and a nanoparticle of 80 atoms were studied as adsorbent substrates of harmful As species. Arsenious (H3AsO3) and arsenic (H3AsO4) acids are physisorbed on the H&S Fe(110) but chemisorbed on the H&S Fe(111) surface. The open-packed plane of the (111) surface, with free active sites, allows better interaction with the acid molecules. The small hydroxylated cluster, Fe32, has shown the best activity as adsorbent of H3AsO3. Electronic charge transfer occurs not only from Fe atoms that directly interact with the acid molecule, but neighbouring Fe atoms are also oxidized. This work presents clear evidence that these spherical Fe aggregates, formed mainly by (111) faces and with an important percentage of low-coordination sites, are excellent adsorbent substrates of H3AsO3 and should be considered as a reference to search for new supported catalysts.

2 citations

Journal ArticleDOI
01 Mar 1994
TL;DR: In this paper, a short outline of structural phase transitions at surfaces and their experimental verification is given as an introduction, which will be followed by a review of experimental and theoretical results for Al and Au surfaces.
Abstract: A short outline of structural phase transitions at surfaces and their experimental verification will be given as an introduction, which will be followed by a review of experimental and theoretical results for Al and Au surfaces. We have studied Au(111)-, Au(110)- and Au(100)-surfaces by medium energy ion scattering (MEIS) experiments and Au(110)- as well as Al(110)-surfaces by low energy electron diffraction (LEED) experiments. At the Au(110) (2×1)-surface deconstruction is accompanied by the disappearance of monoatomic steps. At about 40 K above the deconstruction temperature roughening sets in. The rough surface begins to smoothen if due to the increasing diffusion the outermost layers start to transform into a quasi-liquid state. The growth of the quasi-liquid layer with increasing temperature follows a logarithmic law. Preroughening, roughening and premelting transitions have been detected at the Al(110)-surface. Open questions regarding these phase transitions will be discussed.

1 citations