Download or read book Molecular Orbitals and the Atomistics of Fracture written by M. E. Eberhardt and published by . This book was released on 1981 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-consistent-field Xalpha scattered-wave (SCF-Xa-SW) cluster molecular-orbital models have been constructed for grain-boundary embrittlement of metals. Two specific examples are presented: (1) the embrittlement of nickel by sulfur and (2) the embrittlement of iron by hydrogen. (Author).
Download or read book Atomistics of Fracture written by R.M. Latanison and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1043 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is now more than 100 years since certain detrimental effects on the ductility of iron were first associated with the presence of hydrogen. Not only is hydrogen embrittlement still a major industri al problem, but it is safe to say that in a mechanistic sense we still do not know what hydrogen (but not nitrogen or oxygen, for example) does on an atomic scale to induce this degradation. The same applies to other examples of environmentally-induced fracture: what is it about the ubiquitous chloride ion that induces premature catastrophic fracture (stress corrosion cracking) of ordinarily ductile austenitic stainless steels? Why, moreover, are halide ions troublesome but the nitrate or sulfate anions not deleterious to such stainless steels? Likewise, why are some solid metals embrit tled catastrophically by same liquid metals (liquid metal embrit tlement) - copper and aluminum, for example, are embrittled by liquid mercury. In short, despite all that we may know about the materials science and mechanics of fracture on a macroscopic scale, we know little about the atomistics of fracture in the absence of environmental interactions and even less when embrittlement phe nomena such as those described above are involved. On the other hand, it is interesting to note that physical chemists and surface chemists also have interests in the same kinds of interactions that occur on an atomic scale when metals such as nickel or platinum are used, for example, as catalysts for chemical reactions.
Download or read book Molecular Orbitals and their Energies Studied by the Semiempirical HAM Method written by Einar Lindholm and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: This treatment of molecular and atomic physics is primarily meant as a textbook. It is intended for both chemists and physicists. ·It can be read without much knowledge of quantum mechanics or mathematics, since all such details are explained-. It has developed through a series of lectures at the Royal Institute of Technology. The content is to about 50 % theoretical and to 50 % experimental. The reason why the authors, who are experimentalists, went into theory is the following. When we during the beginning of the 1970's measured photo electron spectra of organic molecules, it appeared to be impossible to understand them by use of available theoretical calculations. To handle hydrocarbons we ( together with C. Fridh ) constructed in 1972 a purely empirical procedure, SPINDO [1] which has proved to be useful, but the extension to molecules with hetero atoms appeared to be difficult. One of us ( L.A.) proposed then another purely ~~E!E!~~! EE2~~~~E~ ( Hydrogenic Atoms in Molecules, HAM/1, unpublished), in which the Fock matrix elements f5..y were parametrized using Slater's shielding concept. The self-repulsion was compensated by a term "-1". The §~~2~~_~ff2E~, HAM/2 [2] , started from the total energy E:. of the molecule. The atomic parts of L used the Slater shielding constants, and the bond parts of E. were taken from SPINDO. The Fock matrix elements Fpv were then obtained from E in a conventional way.
Download or read book Orbitals With Applications In Atomic Spectra Revised Edition written by Charles Stuart Mccaw and published by World Scientific. This book was released on 2020-04-15 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Without being an explicitly philosophical treatise Chas McCaw's book delves into some of the deepest and most difficult aspects of atomic physics and chemistry and its underlying quantum mechanical account … One of the many strengths of the book under review is that it takes a rigorous and unflinching look at the necessary mathematical details. In addition, the author, who is the Head of Science at Winchester College in the UK, provides as many as 107 exercises which are interspersed throughout the main text. The detailed solutions are given at the end of the book, over a sequence of about 50 pages.'Foundations of ChemistryOrbitals: With Applications in Atomic Spectra describes atomic orbitals at a level suitable for undergraduates in chemistry. The mathematical treatment is brought to life by many illustrations rendered from mathematical functions (no artists' impressions), including three-dimensional plots of angular functions, showing orbital phase, and contour plots of the wavefunctions that result from orbital hybridisation.This revised edition includes new discussion of the origins of the colour of gold and the 'accidental degeneracy' of the hydrogen atom subshells, a new figure, a new exercise and worked solution, as well as several new references. It also contains current and accurate updates to the old edition.Orbitals extends the key fundamental quantum properties to many-electron atoms, linear combinations of atomic orbitals, simple molecules, delocalised systems and atomic spectroscopy. By focusing on simple model systems, use of analogies and avoiding group theory, results are obtained from initial postulates without the need for sophisticated mathematics. The book explains topics from first principles and guides the reader carefully through the necessary mathematics, supplemented by worked solutions to problems.
Download or read book Orbitals in Chemistry written by Victor M. S. Gil and published by Cambridge University Press. This book was released on 2000-08-10 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text presents a unified and up-to-date discussion of the role of atomic and molecular orbitals in chemistry, from the quantum mechanical foundations to the recent developments and applications. The discussion is mainly qualitative, largely based on symmetry arguments. It is felt that a sound mastering of the concepts and qualitative interpretations is needed, especially when students are becoming more and more familiar with numerical calculations based on atomic and molecular orbitals. The text is mathematically less demanding than most traditional quantum chemistry books but still retains clarity and rigour. The physical insight is maximized and abundant illustrations are used. The relationships between the more formal quantum mechanical formalisms and the traditional chemical descriptions of chemical bonding are critically established. This book is of primary interest to undergraduate chemistry students and others taking courses of which chemistry is a significant part.
Download or read book Atomic and Molecular Orbital Theory written by Peter O'D. Offenhartz and published by . This book was released on 1970 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Orbital Interactions in Chemistry written by Thomas A. Albright and published by John Wiley & Sons. This book was released on 2013-04-08 with total page 853 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explains the underlying structure that unites all disciplinesin chemistry Now in its second edition, this book explores organic,organometallic, inorganic, solid state, and materials chemistry,demonstrating how common molecular orbital situations arisethroughout the whole chemical spectrum. The authors explore therelationships that enable readers to grasp the theory thatunderlies and connects traditional fields of study withinchemistry, thereby providing a conceptual framework with which tothink about chemical structure and reactivity problems. Orbital Interactions in Chemistry begins by developingmodels and reviewing molecular orbital theory. Next, the bookexplores orbitals in the organic-main group as well as in solids.Lastly, the book examines orbital interaction patterns that occurin inorganic-organometallic fields as well as clusterchemistry, surface chemistry, and magnetism in solids. This Second Edition has been thoroughly revised andupdated with new discoveries and computational tools since thepublication of the first edition more than twenty-five years ago.Among the new content, readers will find: * Two new chapters dedicated to surface science and magneticproperties * Additional examples of quantum calculations, focusing oninorganic and organometallic chemistry * Expanded treatment of group theory * New results from photoelectron spectroscopy Each section ends with a set of problems, enabling readers totest their grasp of new concepts as they progress through the text.Solutions are available on the book's ftp site. Orbital Interactions in Chemistry is written for bothresearchers and students in organic, inorganic, solid state,materials, and computational chemistry. All readers will discoverthe underlying structure that unites all disciplines inchemistry.
Download or read book Introduction to Elementary Molecular Orbital Theory and to Semiempirical Methods written by G.H. Wagniere and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: These notes summarize in part lectures held regularly at the University of Zurich and, in the Summer of 1974, at the Semi nario Latinoamericano de QUimica Cuantica in Mexico. I am grateful to those who have encouraged me to publish these lec tures or have contributed to them by their suggestions. In particular, I wish to thank Professor J. Keller of the Univer sidad Nacional Autonoma in Mexico, Professor H. Labhart and Professor H. Fischer of the University of Zurich, as well as my former students Dr. J. Kuhn, Dr. W. Hug and Dr. R. Geiger. The aim of these notes is to provtde a summary and concise introduction to elementary molecular orbital theory, with an emphasis on semiempirical methods. Within the last decade the development and refinement of ab initio computations has tended to overshadow the usefulness of semiempirical methods. However, both approaches have their justification. Ab initio methods are designed for accurate predictions, at the expense of greater computational labor. The aim of semiempirical methods mainly lies in a semiquantitative classification of electronic pro perties and in the search for regularities within given classes of larger molecules. The reader is supposed to have had some previous basic instruc tion in quantum mechanics, such as is now offered in many uni versities to chemists in their third or fourth year of study. The bibliography should encourage the reader to consult other texts, in particular also selected publications in scientific journals.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book The Fracture of Brittle Materials written by Stephen W. Freiman and published by John Wiley & Sons. This book was released on 2019-01-07 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a modern, practical approach to the understanding and measurement procedures relevant to the fracture of brittle materials This book examines the testing and analysis of the fracture of brittle materials. Expanding on the measurement and analysis methodology contained in the first edition, it covers the relevant measurements (toughness and strength), material types, fracture mechanics, measurement techniques, reliability and lifetime predictions, microstructural considerations, and material/test selection processes appropriate for the analysis of the fracture behavior of brittle materials. The Fracture of Brittle Materials: Testing and Analysis, Second Edition summarizes the concepts behind the selection of a test procedure for fracture toughness and strength, and goes into detail on how the statistics of fracture can be used to assure reliability. It explains the importance of the role of microstructure in these determinations and emphasizes the use of fractographic analysis as an important tool in understanding why a part failed. The new edition includes a significant quantity of material related to the fracture of biomaterials, and features two new chapters—one on thermal shock, the other on the modeling of the fracture process. It also expands on a discussion of how to treat the statistics of fracture strength data to ensure reliability. Provides practical analysis of fracture toughness and strength Introduces the engineering and materials student to the basic concepts necessary for analyzing brittle fracture Contains new statistical analysis procedures to allow for the prediction of the safe design of brittle components Contains real-world examples to assist the reader in applying the concepts to their own research, material development, and quality-control needs The Fracture of Brittle Materials: Testing and Analysis, Second Edition is an important resource for all students, technicians, engineers, scientists, and researchers involved in the study, analysis, creation, or testing of ceramics.
Download or read book Metals Abstracts written by and published by . This book was released on 1996 with total page 1650 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Mechanisms in Materials written by Sidney Yip and published by MIT Press. This book was released on 2023-10-24 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: A student-oriented introduction to understanding mechanisms at the atomistic level controlling macroscopic materials phenomena through molecular dynamics simulations. Machine-learning-based computation in materials innovation, performance optimization, and sustainability offers exciting opportunities at the mesoscale research frontier. Molecular Mechanisms in Materials presents research findings and insights about material behavior at the molecular level and its impact on macroscopic properties. The book’s fifteen essays represent author Sidney Yip’s work in atomistic modeling and materials simulation over more than five decades. The phenomena are grouped into five basic types: fluctuations in simple fluids, crystal melting, plasticity and fracture, glassy relaxations, and amorphous rheology, all focused on molecular mechanisms in base materials. The organizing principle of Molecular Mechanisms in Materials is multiscale modeling and simulation, where conceptual models and simulation techniques are linked across the micro-to-macro length and time scales to control the outcome of specific materials processes. Each essay addresses a specific standalone topic of materials phenomena while also recognizing the larger context of materials science and technology. Individual case studies serve both as standalone essays and companion pieces to each other. Indeed, the global transformation of science and technology is well underway: in his epilogue, Yip discusses the potential of artificial intelligence and machine learning to enhance future materials for societal benefits in the face of global challenges such as climate change, energy sustainability, infrastructure renewal, and nuclear arms control.
Download or read book IUTAM Symposium on Mesoscopic Dynamics of Fracture Process and Materials Strength written by H. Kitagawa and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the papers presented at the IUT AM Symposium of "Mesoscopic Dynamics of Fracture Process and Materials Strength", held in July 2003, at the Hotel Osaka Sun Palace, Osaka, Japan. The Symposium was proposed in 2001, aiming at organizing concentrated discussions on current understanding of fracture process and inhomogeneous deformation governing the materials strength with emphasis on the mesoscopic dynamics associated with evolutional mechanical behaviour under micro/macro mutual interaction. The decision of the General Assembly of International Union of Theoretical and Applied Mechanics (IUT AM) to accept our proposal was well-timed and attracted attention. Driven by the development of new theoretical and computational techniques, various novel challenges to investigate the mesoscopic dynamics have been actively done recently, including large-scaled 3D atomistic simulations, discrete dislocation dynamics and other micro/mesoscopic computational analyses. The Symposium attracted sixty-six participants from eight countries, and forty two papers were presented. The presentations comprised a wide variety of fundamental subjects of physics, mechanical models, computational strategies as well as engineering applications. Among the subjects, discussed are (a) dislocation patterning, (b) crystal plasticity, (c) characteristic fracture of amorphous/nanocrystal, (d) nano-indentation, (e) ductile-brittle transition, (f) ab-initio calculation, (g) computational methodology for multi-scale analysis and others.
Download or read book The Fragment Molecular Orbital Method written by Dmitri Fedorov and published by CRC Press. This book was released on 2009-05-14 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Answering the need to facilitate quantum-chemical calculations of systems with thousands of atoms, Kazuo Kitaura and his coworkers developed the Fragment Molecular Orbital (FMO) method in 1999. Today, the FMO method can be applied to the study of whole proteins and protein-ligand interactions, and is extremely effective in calculating the propertie
Download or read book Technical Abstract Bulletin written by and published by . This book was released on 1981 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mesoscopic Dynamics of Fracture written by Hiroshi Kitagawa and published by Springer Science & Business Media. This book was released on 1998-10-20 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces recent theoretical developments concerning the dynamic behaviour of fracture. Readers learn how the recent development of molecular dynamics and other state-of-the-art methods can help to solve the important problem of fracture from the atomic level.
Download or read book Electron Densities in Molecular and Molecular Orbitals written by J.R. Van Wazer and published by Elsevier. This book was released on 2012-12-02 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron Densities in Molecules and Molecular Orbitals aims to explain the subject of molecular orbitals without having to rely much on its mathematical aspect, making it more approachable to those who are new to quantum chemistry. The book covers topics such as orbitals in quantum-chemical calculations; electronic ionizations and transitions; molecular-orbital change distributions; orbital transformations and calculations not involving orbitals; and electron densities and shapes in atoms and molecules. Also included in the book are the cross-sectional plots of electron densities of compounds such as organic compounds like methane, ethane, and ethylene; monomeric lithium fluoride and monomeric methyl lithium; hydrogen cyanide and methinophosphide; and monomeric borane and diborane. The text is recommended for those who have begun taking an interest in quantum chemistry but do not wish to deal yet with the mathematics part of the subject.
