Electronic Dissipation Processes During Chemical Reactions On Surfaces
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Electronic Dissipation Processes During Chemical Reactions On Surfaces
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Author : Kevin Stella
language : en
Publisher: disserta Verlag
Release Date : 2011
Electronic Dissipation Processes During Chemical Reactions On Surfaces written by Kevin Stella and has been published by disserta Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Science categories.
Every day in our life is larded with a huge number of chemical reactions on surfaces. Some reactions occur immediately, for others an activation energy has to be supplied. Thus it happens that though a reaction should thermodynamically run off, it is kinetically hindered. Meaning the partners react only to the thermodynamically more stable product state within a mentionable time if the activation energy of the reaction is supplied. With the help of catalysts the activation energy of a reaction can be lowered. Such catalytic processes on surfaces are widely used in industry. Around 90% of chemicals are produced via a heterogeneously catalyzed process where a reaction occurs on the surface of a catalyst. However, why is it generally possible that such reactions run off with the help of heterogeneous catalysis, meaning with lower activation energy than without presence of a catalyst? What happens with the energy which is released during a reaction of gas particles on surfaces? How is this energy released, when some part of the energy is transferred to the reactant and some to the chemically active surface? Which physical mechanisms play a key role in the energy transfer? These questions are summarized in the concept of the energy dissipation. To observe this energy dissipation phenomenon, we use a new method, the chemoelectronics. With this method we try to detect the released energy, induced by reactions on surfaces, via thin-layered electronic device elements. An aim of this work is to build up very sensitive chemoelectronic sensors to measure electronic excitations released during such simple reactions of molecules as adsorption and desorption and more complicated reactions as the water formation reaction. Therefore a new line of chemoelectronic sensors is developed and characterized in terms of internal photoemission and stability. Meaning the previously used aluminum (Al-AlOx-Ag) and tantalum based (Ta-TaOx-Au) metal-insulator-metal sensors (MIM) are tested and new titanium based (Ti-TiOx-Au) MIMs are developed. Additionally silicon based stepped-metal-insulator-semiconductor sensors (stepped-MIS, Si-SiOx-Au, Si-SiOx-Pt) are set up and characterized. For the characterization of the chemoelectronic sensors the process of internal photoemission is used. Both, chemical- and photoexcitation release hot charge carriers (electrons and holes). Due to the existence of excited carriers in the sensor, a current can be measured without applying a bias voltage. It will be shown that the chemo- and the photosensitivity are strongly related to each other. As a first experiment for the chemical selectivity of the detectors, a stream of excited hydrogen molecules and hydrogen atoms is used. The excitation and radical formation is produced by the interaction of ground state molecules with a hot tungsten surface according to the pioneering experiments of Irving Langmuir. Additionally, excited oxygen beams are studied in this work.
Dynamics At Surfaces Understanding Energy Dissipation And Physicochemical Processes At The Atomic And Molecular Level
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Author : Marco Sacchi
language : en
Publisher: Frontiers Media SA
Release Date : 2024-04-26
Dynamics At Surfaces Understanding Energy Dissipation And Physicochemical Processes At The Atomic And Molecular Level written by Marco Sacchi and has been published by Frontiers Media SA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-04-26 with Science categories.
Energy release to solid interfaces following chemical reactions is ubiquitous in a vast range of phenomena. Energy dissipation and dynamical disorder (surface entropy), surface friction and molecular diffusion control the rates of heterogeneous catalytic reactions, the efficiency of novel technology, lubrication as well as materials growth including self-assembly and nano-structures. Yet we understand little about the underlying nature of these mechanisms. Fundamentally, energy dissipation including interactions with phonons and electron-hole pairs determines the lifetime of molecular vibrations and rotations as well as the decoherence rate of quantum states. These processes form a central point for many aspects in physical chemistry, are embedded in the mechanisms that control surface dynamical processes and are critical factors in catalysis. They are equally relevant for physicochemical processes in the Earth's atmosphere and astrochemistry occurring on cosmic dust grains.
Encyclopedia Of Interfacial Chemistry
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Author :
language : en
Publisher: Elsevier
Release Date : 2018-03-29
Encyclopedia Of Interfacial Chemistry written by and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-03-29 with Science categories.
Encyclopedia of Interfacial Chemistry: Surface Science and Electrochemistry, Seven Volume Set summarizes current, fundamental knowledge of interfacial chemistry, bringing readers the latest developments in the field. As the chemical and physical properties and processes at solid and liquid interfaces are the scientific basis of so many technologies which enhance our lives and create new opportunities, its important to highlight how these technologies enable the design and optimization of functional materials for heterogeneous and electro-catalysts in food production, pollution control, energy conversion and storage, medical applications requiring biocompatibility, drug delivery, and more. This book provides an interdisciplinary view that lies at the intersection of these fields. Presents fundamental knowledge of interfacial chemistry, surface science and electrochemistry and provides cutting-edge research from academics and practitioners across various fields and global regions
Electronic Processes At Solid Surfaces
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Author : E. Ilisca
language : en
Publisher: World Scientific
Release Date : 1996
Electronic Processes At Solid Surfaces written by E. Ilisca and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 1996 with Science categories.
The subject of surface physics has now grown to become an exciting interdisciplinary field of research with important practical applications.The purpose of this book is to provide a guided tour of some recent advances, key research issues and approaches in electronic processes at solid surfaces.Apart from a few structural studies, selected topics have been chosen to illustrate the dynamical response of the solid surface to external probes, with the main emphasis on electron transfer phenomena.
Journal Of Research Of The National Institute Of Standards And Technology
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Author :
language : en
Publisher:
Release Date : 1991
Journal Of Research Of The National Institute Of Standards And Technology written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1991 with Chemistry categories.
Reports NIST research and development in the physical and engineering sciences in which the Institute is active. These include physics, chemistry, engineering, mathematics, and computer sciences. Emphasis on measurement methodology and the basic technology underlying standardization.
Dynamics
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Author :
language : en
Publisher: Elsevier
Release Date : 2008-10-09
Dynamics written by and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-10-09 with Science categories.
This volume of the Handbook of Surface Science covers all aspects of the dynamics of surface processes. Two dozen world leading experts in this field address the subjects of energy exchange in gas atoms, surface collisions, the rules governing dissociative adsorption on surfaces, the formation of nanostructures on surfaces by self-assembly, and the study of surface phenomena using ultra-fast lasers. The chapters are written for both newcomers to the field as well as researchers. • Covers all aspects of the dynamics of surface processes • Provides understanding of this unique field utilizing a multitude of accurate experiments and advanced microscopic theory that allows quantum-level comparisons • Presents the concepts and tools relevant beyond surface science for catalysis, nanotechnology, biology, medicine, and materials
Current Trends Of Surface Science And Catalysis
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Author : Jeong Young Park
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-10-23
Current Trends Of Surface Science And Catalysis written by Jeong Young Park and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-10-23 with Science categories.
This unique book covers the latest surface science studies on model catalysts, including single crystals, non-colloidal nanocatalysts, and nanoparticles in various forms with the control of size, shape and composition. This book addresses the issue of bridging “materials and pressure gaps” and also discusses the important issue of metal-oxide interface and hot electron flows in heterogeneous catalysis. The current development of in-situ surface techniques that is relevant to bridging “pressure gaps” is also highlighted.
Frontiers And Challenges In Warm Dense Matter
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Author : Frank Graziani
language : en
Publisher: Springer Science & Business
Release Date : 2014-04-28
Frontiers And Challenges In Warm Dense Matter written by Frank Graziani and has been published by Springer Science & Business this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-04-28 with Computers categories.
Warm Dense Matter (WDM) occupies a loosely defined region of phase space intermediate between solid, liquid, gas, and plasma, and typically shares characteristics of two or more of these phases. WDM is generally associated with the combination of strongly coupled ions and moderately degenerate electrons, and careful attention to quantum physics and electronic structure is essential. The lack of a small perturbation parameter greatly limits approximate attempts at its accurate description. Since WDM resides at the intersection of solid state and high energy density physics, many high energy density physics (HEDP) experiments pass through this difficult region of phase space. Thus, understanding and modeling WDM is key to the success of experiments on diverse facilities. These include the National Ignition Campaign centered on the National Ignition Facility (NIF), pulsed-power driven experiments on the Z machine, ion-beam-driven WDM experiments on the NDCX-II, and fundamental WDM research at the Linear Coherent Light Source (LCLS). Warm Dense Matter is also ubiquitous in planetary science and astrophysics, particularly with respect to unresolved questions concerning the structure and age of the gas giants, the nature of exosolar planets, and the cosmochronology of white dwarf stars. In this book we explore established and promising approaches to the modeling of WDM, foundational issues concerning the correct theoretical description of WDM, and the challenging practical issues of numerically modeling strongly coupled systems with many degrees of freedom.
Energy Dissipation In Molecular Systems
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Author : André Tramer
language : en
Publisher: Springer Science & Business Media
Release Date : 2005-12-27
Energy Dissipation In Molecular Systems written by André Tramer and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005-12-27 with Science categories.
Energy Dissipation in Molecular Systems analyzes experimental data on the redistribution and dissipation of energy injected into molecular systems by radiation or charged particles. These processes, competing with such practically important relaxation channels as chemical reaction or stimulated emission (laser action), are the primary focus in this monograph. Among other topics, the book treats vibrational redistribution and electronic relaxation in isolated molecules and the effects of inter-molecular interactions (collisions, complex formation, solvent effects) on the relaxation paths. Primary photo-chemical processes (such as isomerization, proton or hydrogen-atom transfer, electron transfer and ionization) are also treated as particular cases of vibrational or electronic relaxation. Only a basic knowledge of quantum mechanics and spectroscopy is assumed and calculations are kept to a strict minimum, making the book more accessible to students.
Vibrations At Surfaces
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Author : R. Caudano
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Vibrations At Surfaces written by R. Caudano and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Science categories.
This volume contains most of the invited and contributed papers presented at the second international conference devoted to the general topic "Vibrations at Surfaces" and which took place from 10 to 12 September 1980 at the Facu1tes Notre-Dame de 1a Paix in Namur, Belgium. The conference was organized to review the large amount of information gathered in this field over the late seventies as a result of th~ rapid improvements and dissemination of surface spectroscopic technique such a electron energy loss, infrared and Raman surface spectroscopies. Much time was devoted to Raman spectroscopy of adsorbed mo1e 'cu1es. After several years of vivid debate over the causes of the observed large enhancement of Raman cross section, a clearer pic ture emerges from the papers presented here: the actual value of the enhancement factor does depend in a complicated manner on long range surface roughness, atomic-scale roughness and the dielectric properties of the substrate as well as on the electronic structure of the molecule in its adsorbed state. Less controversial are the results obtained with electron energy loss spectroscopy (EELS) and several sessions of the con ference were devoted to the approach. As witnessed by the growing number of laboratories using the technique, EELS is now a mature spectroscopic tool for the characterization and analysis of the chemisorption bond.