Download or read book Describing the Electronic Structure of Molecules on Metal Surfaces written by Justin Moore and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurately describing the electronic structure of molecules on metal surfaces is key to correctlymodeling their surface-enhanced properties. These properties are the basis for a variety of topicsin chemistry, such as single molecule spectroscopy and organic photovoltaic systems. In fact,the most recent Nobel Prize in Chemistry was awarded for work in the eld of single moleculeuorescence. While single-molecule uorescence is now widely used within both the chemical andbiochemical communities, its spectroscopic signal gives very little information about the structureand identity of the uorophore. Surface enhanced Raman spectroscopy (SERS), on the otherhand, can be used to uniquely identify a molecule as well detect the presence of a known scatterer.Raman diers from uorescence, as its the result of the inelastic scattering of photons by amolecule rather than an absorption process. These scattered photons contain information aboutthe vibrational and rotational states within the molecule, similar to IR spectroscopic techniques.However, the Raman signal from a single molecule is very weak. The mechanisms behind SERSprovide sucient enhancement to enable single molecule detection and identication. ModelingSERS and other surface-enhanced properties is dicult due to the complex interactions betweenthe molecule and the metal surface. In order to accurately describe how these interactions impactthe electronic structure, we require rst-principles based methods. Density functional theory(DFT) remains the go-to method for simulations of large systems thanks to its balance betweenaccuracy and computational complexity. However, one encounters certain failures within DFTthat limit its application to accurately describing the interactions between molecules and metalsurfaces. In principle, DFT is an exact method if one knows the correct exchange-correlation(XC) potential. In practice, this potential is only an approximation determined by an XCfunctional. Many XC functionals exist and the accuracy of a DFT calculation is highly dependenton the choice of XC. Recently, a new class of XC functionals called long-range corrected (LC)functionals have been developed that show signicant improvement to the traditional failures ofDFT. Of particular interest is their ability to be `tuned' in order to enforce properties that theexact XC functional would have. In this dissertation, we present the importance of using LCfunctionals when describing the electronic structure of molecules on metal surfaces using DFT.We rst demonstrate how LC functionals improve the description of the energy gap betweenthe frontier orbitals for a set of substituted pyridines on a small silver cluster. This allowsfor a better prediction to the magnitude of the SERS enhancement. While DFT is capable ofdescribing `large' systems on the order of hundreds of atoms, realistically sized nanoparticles withdimensions on the order of 1 to 100 nm can contain between 300 and 10,000,000 atoms, makingthem computationally intractable even for DFT. In order to go beyond small metal clusters, we have developed a hybrid model that combines a quantum mechanical description of a moleculesusing density functional theory (DFT) with a classical atomistic electrodynamics model of themetal system. We present here a new implementation of the discrete interaction model/quantummechanical (DIM/QM) method within the NWChem computational package. We demonstratethat by combining DIM/QM with the tuning of LC functionals, we can accurately describe thechanges in electronic structure seen when molecules approach a metal surface at a signicantlyreduced computational cost compared to other methods. These changes are important to capturein a metal-molecule system, as they signicantly alter the molecule's optical properties. Inaddition, we have made several improvements to the underlying DIM/QM algorithm whichdecrease the computational cost of DIM/QM by 30%. Furthermore, we extend DIM toaccount for experimentally observed changes in the optical properties of metal nanoparticles withdimensions less than

Download or read book Electronic Structure and Reactivity of Metal Surfaces written by E. Derouane and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: Imagine that a young physicist would approach a granting agen cy and propose to contribute to heterogeneous catalysis by studying the heat conductivity of gases in contact with a hot filament. How would he be received now? How would he have been treated sixty years ago ? Yet, more than sixty years ago, Irving Langmuir, through his study of heat transfer from a tungsten filament, uncovered most of the fundamental ideas which are used to-day by the scientific com munity in pure and applied heterogeneous catalysis. Through his work with what were for the first time "clean" metal surfaces, Langmuir formulated during a period of a little over ten years un til the early thirties, the concepts of chemisorption, monolayer, adsorption sites, adsorption isotherm, sticking probability, cata lytic mechanisms by way of the interaction between chemisorbed spe cies, behavior of non-uniform surfaces and repulsion between adsor bed dipoles. It is fair to say that many of these ideas constituting the first revolution in surface chemistry have since been refined through thousands of investigations. Countless papers have been pu blished on the subject of the Langmuir adsorption isotherm, the Langmuir catalytic kinetics and the Langmuir site-exclusion adsorp tion kinetics. The refinements have been significant. ThE original concepts in their primitive or amended form are used everyday by catalytic chemists and chemical engineers allover the world in their treatment of experimental data, design of reactors or inven tion of new processes.

Download or read book Chemical Bonding at Surfaces and Interfaces written by Anders Nilsson and published by Elsevier. This book was released on 2011-08-11 with total page 533 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular surface science has made enormous progress in the past 30 years. The development can be characterized by a revolution in fundamental knowledge obtained from simple model systems and by an explosion in the number of experimental techniques. The last 10 years has seen an equally rapid development of quantum mechanical modeling of surface processes using Density Functional Theory (DFT). Chemical Bonding at Surfaces and Interfaces focuses on phenomena and concepts rather than on experimental or theoretical techniques. The aim is to provide the common basis for describing the interaction of atoms and molecules with surfaces and this to be used very broadly in science and technology. The book begins with an overview of structural information on surface adsorbates and discusses the structure of a number of important chemisorption systems. Chapter 2 describes in detail the chemical bond between atoms or molecules and a metal surface in the observed surface structures. A detailed description of experimental information on the dynamics of bond-formation and bond-breaking at surfaces make up Chapter 3. Followed by an in-depth analysis of aspects of heterogeneous catalysis based on the d-band model. In Chapter 5 adsorption and chemistry on the enormously important Si and Ge semiconductor surfaces are covered. In the remaining two Chapters the book moves on from solid-gas interfaces and looks at solid-liquid interface processes. In the final chapter an overview is given of the environmentally important chemical processes occurring on mineral and oxide surfaces in contact with water and electrolytes. Gives examples of how modern theoretical DFT techniques can be used to design heterogeneous catalysts This book suits the rapid introduction of methods and concepts from surface science into a broad range of scientific disciplines where the interaction between a solid and the surrounding gas or liquid phase is an essential component Shows how insight into chemical bonding at surfaces can be applied to a range of scientific problems in heterogeneous catalysis, electrochemistry, environmental science and semiconductor processing Provides both the fundamental perspective and an overview of chemical bonding in terms of structure, electronic structure and dynamics of bond rearrangements at surfaces

Download or read book Reactions of Organic Molecules on Metal Surfaces Studied by STM written by Markus Wahl and published by Cuvillier Verlag. This book was released on 2007 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Excited States in Quantum Chemistry written by Cleanthes A. Nicolaides and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is undoubtedly true that much of the progress in the quant~m theory of matter is due to the remarkable success of the independent particle model (IPM)--especially in describing ground states. However, the accurate experimental results of the last 10 years or so, on a variety of spectroscopic phenomena and chemical processes which involve the Excited State, and the related failure of the IPM to reproduce accurately--in many cases, even qualitatively--the observed data, have sent to theorists a clear message: There is need to create and/or apply general and useful approaches to the many-electron problem of the excited state which go beyond the IPM, treat electron correlation and relativity and explain or predict all relevant physical or chemical information with consistent accuracy. This book contains articles devoted mainly to some of the most important new developments in Quantum Chemistry concerning the theoretical foundations and the computational implementation of many-body approaches to the quantitative and detailed under standing of the electronic excited states of atoms, molecules and solids. Furthermore, it contains experimental and pheno menological articles on Photoelectron and Auger spectroscopy, Lifetime measurements and Organic Photochemistry. In combination or individually, these articles constitute a good description of some current theoretical and experimental work on the electronic structure and spectroscopy of atoms, molecules, polymers, surfaces, metal oxides and amorphous solids.

Download or read book Interaction of Atoms and Molecules with Solid Surfaces written by V. Bortolani and published by Springer Science & Business Media. This book was released on 2013-11-22 with total page 693 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is considerable interest, both fundamental and technological, in the way atoms and molecules interact with solid surfaces. Thus the description of heterogeneous catalysis and other surface reactions requires a detailed understand ing of molecule-surface interactions. The primary aim of this volume is to provide fairly broad coverage of atoms and molecules in interaction with a variety of solid surfaces at a level suitable for graduate students and research workers in condensed matter physics, chemical physics, and materials science. The book is intended for experimental workers with interests in basic theory and concepts and had its origins in a Spring College held at the International Centre for Theoretical Physics, Miramare, Trieste. Valuable background reading can be found in the graduate-Ievel introduction to the physics of solid surfaces by ZangwilI(1) and in the earlier works by Garcia Moliner and F1ores(2) and Somorjai.(3) For specifically molecule-surface interac tions, additional background can be found in Rhodin and Ertl(4) and March.(S) V. Bortolani N. H. March M. P. Tosi References 1. A. Zangwill, Physics at Surfaces, Cambridge University Press, Cambridge (1988). 2. F. Garcia-Moliner and F. Flores, Introduction to the Theory of Solid Surfaces, Cambridge University Press, Cambridge (1979). 3. G. A. Somorjai, Chemistry in Two Dimensions: Surfaces, Cornell University Press, Ithaca, New York (1981). 4. T. N. Rhodin and G. Erd, The Nature of the Surface Chemical Bond, North-Holland, Amsterdam (1979). 5. N. H. March, Chemical Bonds outside Metal Surfaces, Plenum Press, New York (1986).

Download or read book Electronic Structure written by Richard M. Martin and published by Cambridge University Press. This book was released on 2020-08-27 with total page 791 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of electronic structure of materials is at a momentous stage, with new computational methods and advances in basic theory. Many properties of materials can be determined from the fundamental equations, and electronic structure theory is now an integral part of research in physics, chemistry, materials science and other fields. This book provides a unified exposition of the theory and methods, with emphasis on understanding each essential component. New in the second edition are recent advances in density functional theory, an introduction to Berry phases and topological insulators explained in terms of elementary band theory, and many new examples of applications. Graduate students and research scientists will find careful explanations with references to original papers, pertinent reviews, and accessible books. Each chapter includes a short list of the most relevant works and exercises that reveal salient points and challenge the reader.

Download or read book Electronic Structure of Metal Phthalocyanines on Ag 100 written by Cornelius Krull and published by Springer Science & Business Media. This book was released on 2013-11-19 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: The application of molecules in technological devices hinges on the proper understanding of their behavior on metallic electrodes or substrates. The intrinsic molecular electronic and magnetic properties are modified at a metallic interface, and greatly depend on the atomic configuration of the molecule-metal bond. This poses certain problems, such as the lack of reproducibility in the transport properties of molecular junctions, but also offers the possibility to induce new charge and spin configurations that are only present at the interface. The results presented in this thesis address this issue, providing a comprehensive overview of the influence of molecule-metal and molecule-molecule interactions on the electronic and magnetic properties of molecules adsorbed on metallic substrates. Using metal-phthalocyanines (MePc), a commonly used metal-organic complex as a model system, each chapter explores different aspects of the interaction with silver surfaces: the local adsorption geometry, self-assembly, the modifications of the electronic and magnetic characteristics due to hybridization and charge transfer, and finally the manipulation of molecular charge and spin states by electron doping using alkali atoms moved with the STM tip.

Download or read book Electronic Structure of Materials written by Adrian P. Sutton and published by Clarendon Press. This book was released on 1993-09-30 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the modern real-space approach to electronic structures and properties of crystalline and non-crystalline materials in a form readily accessible to undergraduates in materials science, physics, and chemistry. - ;This book describes the modern real-space approach to electronic structures and properties of crystalline and non-crystalline materials in a form readily accessible to undergraduates in materials science, physics, and chemistry. -

Download or read book Electronic Structure and the Properties of Solids written by Walter A. Harrison and published by Courier Corporation. This book was released on 1989-07-01 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Should be widely read by practicing physicists, chemists and materials scientists." — Philosophical Magazine In this comprehensive and innovative text, Professor Harrison (Stanford University) offers a basic understanding of the electronic structure of covalent and ionic solids, simple metals, transition metals, and their compounds. The book illuminates the relationships of the electronic structures of these materials and shows how to calculate dielectric, conducting, and bonding properties for each. Also described are various methods of approximating electronic structure, providing insight and even quantitative results from the comparisons. Dr. Harrison has also included an especially helpful "Solid State Table of the Elements" that provides all the parameters needed to estimate almost any property of any solid, with a hand-held calculator, using the techniques developed in the book. Designed for graduate or advanced undergraduate students who have completed an undergraduate course in quantum mechanics or atomic and modern physics, the text treats the relation between structure and properties comprehensively for all solids rather than for small classes of solids. This makes it an indispensable reference for all who make use of approximative methods for electronic-structure engineering, semiconductor development and materials science. The problems at the ends of the chapters are an important aspect of the book. They clearly show that the calculations for systems and properties of genuine and current interest are actually quite elementary. Prefaces. Problems. Tables. Appendixes. Solid State Table of the Elements. Bibliography. Author and Subject Indexes. "Will doubtless exert a lasting influence on the solid-state physics literature." — Physics Today

Download or read book The Electronic Structure and Chemistry of Solids written by P. A. Cox and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'The Electronic Structure and Chemistry of Solids' shows how the electronic structures and properties of solids can be described in terms familiar to chemists. Recent years have seen a considerable growth of interest in chemical aspects of the electronic structure of solids. The first three chapters give a fairly elementary account of the topics. The later chapters present slightly more advanced aspects, including many topics of current research interest, such as metal-insulator transitions, low-dimensional solids and 'molecular metals', and the properties of surfaces. The discussion is illustrated by a wide variety of examples.

Download or read book Electronic Structure Correlation Effects and Physical Properties of D and F metals and Their Compounds written by Valentin Yu Irkhin and published by Cambridge Int Science Publishing. This book was released on 2007 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book includes all main physical properties of d- and f-transition-metal systems and corresponding theoretical concepts. Special attention is paid to the theory of magnetism and transport phenomena. Some examples of non-traditional questions which are treated in detail in the book: the influence of density of states singularities on electron properties; many-electron description of strong itinerant magnetism; mechanisms of magnetic anisotropy; microscopic theory of anomalous transport phenomena in ferromagnets. Besides considering classical problems of solid state physics as applied to transition metals, modern developments in the theory of correlation effects in d- and f-compounds are considered within many-electron models. The book contains, where possible, a simple physical discussion. More difficult questions are considered in Appendices.

Download or read book Atomic and Electronic Structure of Surfaces written by Michel Lannoo and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 267 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surfaces and interfaces play an increasingly important role in today's solid state devices. In this book the reader is introduced, in a didactic manner, to the essential theoretical aspects of the atomic and electronic structure of surfaces and interfaces. The book does not pretend to give a complete overview of contemporary problems and methods. Instead, the authors strive to provide simple but qualitatively useful arguments that apply to a wide variety of cases. The emphasis of the book is on semiconductor surfaces and interfaces but it also includes a thorough treatment of transition metals, a general discussion of phonon dispersion curves, and examples of large computational calculations. The exercises accompanying every chapter will be of great benefit to the student.

Download or read book Physics and Chemistry at Oxide Surfaces written by Claudine Noguera and published by Cambridge University Press. This book was released on 1996-09-28 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first chapter of the book summarizes classical approaches, introduces the concept of ionicity, and describes the mixed iono-covalent character of the oxygen cation bond in bulk materials. The next three chapters focus on the characteristics of the atomic structure (relaxation, rumpling and reconstruction effects), the electronic structure (band width, gap width, etc.) and the excitations of clean surfaces.

Download or read book Electrons In Metals And Alloys written by J. A. Alonso and published by Academic Press. This book was released on 2012-12-02 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a broad review of the electronic structure of metals and alloys. It emphasises the way in which the behavior of electrons in these materials governs the thermodynamic and other properties of these conducting materials. The theoretical treatment proceeds from a wave mechanics approach to more sophisticated techniques for the description of the properties of metals and alloys.

Download or read book Modern Electronic Structure Theory written by David Yarkony and published by World Scientific. This book was released on 1995 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern Electronic Structure Theory provides a didactically oriented description of the latest computational techniques in electronic structure theory and their impact in several areas of chemistry. The book is aimed at first year graduate students or college seniors considering graduate study in computational chemistry, or researchers who wish to acquire a wider knowledge of this field.

Download or read book Semiempirical Methods of Electronic Structure Calculation written by Gerald Segal and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: If one reflects upon the range of chemical problems accessible to the current quantum theoretical methods for calculations on the electronic structure of molecules, one is immediately struck by the rather narrow limits imposed by economic and numerical feasibility. Most of the systems with which experimental photochemists actually work are beyond the grasp of ab initio methods due to the presence of a few reasonably large aromatic ring systems. Potential energy surfaces for all but the smallest molecules are extremely expensive to produce, even over a restricted group of the possible degrees of freedom, and molecules containing the higher elements of the periodic table remain virtually untouched due to the large numbers of electrons involved. Almost the entire class of molecules of real biological interest is simply out of the question. In general, the theoretician is reduced to model systems of variable appositeness in most of these fields. The fundamental problem, from a basic computational point of view, is that large molecules require large numbers of basis functions, whether Slater type orbitals or Gaussian functions suitably contracted, to provide even a modestly accurate description of the molecular electronic environment. This leads to the necessity of dealing with very large matrices and numbers of integrals within the Hartree-Fock approximation and quickly becomes both numerically difficult and uneconomic.