Atomic Structure Studies of Holmium on SI(111) Surface by Low Energy Electron Diffraction Patterson Inversion at Multiple Incident Angles PDF Download

Author: Ai-chi Leung (Angela)
Publisher:
ISBN:
Category : Atomic structure
Languages : en
Pages : 124

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Author:
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Category :
Languages : en
Pages :

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Author:
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Category :
Languages : en
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The structures of molecular crystal surfaces were investigated for the first time by the use of low-energy electron diffraction (LEED). The experimental results from a variety of molecular crystals were examined and compared as a first step towards understanding the properties of these surfaces on a microscopic level. The method of sample preparation employed, vapor deposition onto metal single-crystal substrates at low temperatures in ultrahigh vacuum, allowed concurrent study of the structures of adsorbed monolayers on metal surfaces and of the growth processes of molecular films on metal substrates. The systems investigated were ice, ammonia, naphthalene, benzene, the n-paraffins (C3 to C), cyclohexane, trioxane, acetic acid, propionic acid, methanol, and methylamine adsorbed and condensed on both Pt(111) and Ag(111) surfaces. Electron-beam-induced damage of the molecular surfaces was observed after electron exposures of 10−4 A sec cm−2 at 20 eV. Aromatic molecular crystal samples were more resistant to damage than samples of saturated molecules. The quality and orientation of the grown molecular crystal films were influenced by substrate preparation and growth conditions. Forty ordered monolayer structures were observed. 110 figures, 22 tables, 162 references.

Author: Mirtat Bouroushian
Publisher: Springer Science & Business Media
ISBN: 3642039677
Category : Science
Languages : en
Pages : 365

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The author provides a unified account of the electrochemical material science of metal chalcogenide (MCh) compounds and alloys with regard to their synthesis, processing and applications. Starting with the chemical fundamentals of the chalcogens and their major compounds, the initial part of the book includes a systematic description of the MCh solids on the basis of the Periodic Table in terms of their structures and key properties. This is followed by a general discussion on the electrochemistry of chalcogen species, and the principles underlying the electrochemical formation of inorganic compounds/alloys. The core of the book offers an insight into available experimental results and inferences regarding the electrochemical preparation and microstructural control of conventional and novel MCh structures. It also aims to survey their photoelectrochemistry, both from a material-oriented point of view and as connected to specific processes such as photocatalysis and solar energy conversion. Finally, the book illustrates the relevance of MCh materials to various applications of electrochemical interest such as (electro)catalysis in fuel cells, energy storage with intercalation electrodes, and ion sensing.

Author: Tapan Chatterji
Publisher: Elsevier
ISBN: 0080457053
Category : Science
Languages : en
Pages : 574

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Neutron Scattering from Magnetic Materials is a comprehensive account of the present state of the art in the use of the neutron scattering for the study of magnetic materials. The chapters have been written by well-known researchers who are at the forefront of this field and have contributed directly to the development of the techniques described. Neutron scattering probes magnetic phenomena directly. The generalized magnetic susceptibility, which can be expressed as a function of wave vector and energy, contains all the information there is to know about the statics and dynamics of a magnetic system and this quantity is directly related to the neutron scattering cross section. Polarized neutron scattering techniques raise the sophistication of measurements to even greater levels and gives additional information in many cases. The present book is largely devoted to the application of polarized neutron scattering to the study of magnetic materials. It will be of particular interest to graduate students and researchers who plan to investigate magnetic materials using neutron scattering.· Written by a group of scientist who have contributed directly in developing the techniques described.· A complete treatment of the polarized neutron scattering not available in literature.· Gives practical hits to solve magnetic structure and determine exchange interactions in magnetic solids.· Application of neutron scattering to the study of the novel electronic materials.

Author: Ute Kolb
Publisher: Springer
ISBN: 9789400755857
Category : Science
Languages : en
Pages : 434

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The polycrystalline and nanocrystalline states play an increasingly important role in exploiting the properties of materials, encompassing applications as diverse as pharmaceuticals, catalysts, solar cells and energy storage. A knowledge of the three-dimensional atomic and molecular structure of materials is essential for understanding and controlling their properties, yet traditional single-crystal X-ray diffraction methods lose their power when only polycrystalline and nanocrystalline samples are available. It is here that powder diffraction and single-crystal electron diffraction techniques take over, substantially extending the range of applicability of the crystallographic principles of structure determination. This volume, a collection of teaching contributions presented at the Crystallographic Course in Erice in 2011, clearly describes the fundamentals and the state-of-the-art of powder diffraction and electron diffraction methods in materials characterisation, encompassing a diverse range of disciplines and materials stretching from archeometry to zeolites. As such, it is a comprehensive and valuable resource for those wishing to gain an understanding of the broad applicability of these two rapidly developing fields.

Author:
Publisher: DIANE Publishing
ISBN: 9781422318324
Category :
Languages : en
Pages : 18

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Author: Alexey A. Popov
Publisher: Springer
ISBN: 9783319836485
Category : Technology & Engineering
Languages : en
Pages : 328

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This book discusses recent progress in endohedral fullerenes – their production and separation techniques, as well as their characterization and properties. Furthermore, the book delves into the all-important issue of stability by investigating electron transfer between the encapsulated metal species and the carbon cage. It also reviews spin-based phenomena caused by the shielding of endohedral spin by the fullerene, and analyzes formation of the spin states by charge transfer as studied by electron spin resonance. Tuning of charge states of endohedral species and of spin states of both the cage and the cluster are explained. Finally, the book considers the recent discovery of magnetism in some endohedral fullerenes, and the potential for quantum computing.

Author: Yurii A. Izyumov
Publisher: Springer Science & Business Media
ISBN: 1468407120
Category : Science
Languages : en
Pages : 607

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The inter action between the magnetic field generated by the neutron and the magnetic moment of atoms containing unpaired electrons was experimentally demonstrated for the first time about twenty years ago. The basic theory describing such an in teraction had already been developed and the first nuclear reactors with large available thermal neutron fluxes had recently been con structed. The power of the magnetic neutron interaction for in vestigating the structure of magnetic materials was immediately recognized and put to use where possible. Neutron diffraction, however, was practicable only in countries with nuclear reactors. The earliest neutron determinations of magnetic ordering were hence primarily carried out at Oak Ridge and Brookhaven in the US, at Chalk River in Canada and at Harwell in England. Diffraction patterns from polycrystalline ferromagnets and antiferromagnets are interpretable if produced by simple spin arrays. More complex magnetic scattering patterns could often be unravelled, in terms of a three-dimensional array of atomic moments, if the specimen studied is a single crystal. The devel opment of sophisticated cryogenic equipment, with independently alignable magnetic fields, opened the way to greater complexity in the magnetic structures that could be successfully determined, as did also the introduction of polarized neutron beams. By the end of the 'sixties, many countries were contributing significantly to neutron diffraction studies of a wide variety of magnetic materials.

Author: Mansoor Niaz
Publisher: Routledge
ISBN: 1136941959
Category : Education
Languages : en
Pages : 355

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How teachers view the nature of scientific knowledge is crucial to their understanding of science content and how it can be taught. This book presents an overview of the dynamics of scientific progress and its relationship to the history and philosophy of science, and then explores their methodological and educational implications and develops innovative strategies based on actual classroom practice for teaching topics such the nature of science, conceptual change, constructivism, qualitative-quantitative research, and the role of controversies, presuppositions, speculations, hypotheses, and predictions. Field-tested in science education courses, this book is designed to involve readers in critically thinking about the history and philosophy of science and to engage science educators in learning how to progressively introduce various aspects of ‘science-in-the-making’ in their classrooms, to promote discussions highlighting controversial historical episodes included in the science curriculum, and to expose their students to the controversies and encourage them to support, defend or critique the different interpretations. Innovating Science Teacher Education offers guidelines to go beyond traditional textbooks, curricula, and teaching methods and innovate with respect to science teacher education and classroom teaching.