Download or read book Electron Dynamics and Symmetries at the Metal Molecule Interface Probed by Two Photon Photoemission written by Eric Anton Muller and published by . This book was released on 2012 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Femtosecond, angle resolved two photon photoemission spectroscopy is used as a probe of the metal-molecule interface. In four related investigations, monolayer or submonolayer coverages of a molecule are adsorbed onto an Ag(111) surface under ultrahigh vacuum conditions. Studies use a an optically excited electronic probe to investigate to probe the energetic landscape experienced and the response of a molecular adsorbate to an excess charge. Energy levels, electronic population, and band structure reveal molecular structure and mechanisms of dynamic response to an injected charge. Room temperature ionic liquids (RTIL), consisting of charge separated anions and cations, represent a new and poorly understood class of electrochemical solvents. The mechanism of electron solvation has been proposed to be vastly different at the electrode interface than has been observed in bulk studies. Optical excitation into the RTIL conduction band results in a localized excess charge, as measured by band dispersions. Electron solvation is measured directly as the photoemitted kinetic energy. Solvation by 200-540 meV is found to occur rapidly on the timescale of 350 fs, supporting previous predictions of fast charge solvation at the interface. Further, a previously proposed phase transition is observed between a low temperature ordered phase and high temperature disordered phase. This phase transition, which occurs at 250 K, is quantified by both the change in workfunction and a change in the energy of solvation between the two phases. The image state is often used as a sensitive probe of molecular films, however, the electronic potential experienced by the image state electron is poorly understood. Theoretical predictions of image state energy in molecular films with a positive electron affinity are often wrong by 1-3 eV, and descriptions of the band structure typically remain limited to a measurement of effective mass. An image state is investigated within a film of metallated phthalocyanines. Phthalocyanines crystallize laying flat on the substrate, with a nearly square unit cell of 14 - 15 Å on a side. Angle resolved measurements into the second Brillouin zone reveal folding of the image state due to interactions with the screened potential energy surface within the molecule. The bandgap, measured to be 150 meV, can be used to estimate the corrugation of the energy landscape. Further, a Kronig Penney model is quantitatively compared to the first several backfolded image bands. Comparision between theory and experiment reveals the effects of the fourfold symmetry of lattice on the image state bandstructure. The morphology and crystal structure of thin film molecular semiconductors is well known to directly influence the band structure and electronic properties of the material. Further, several morphologies and crystal structures can result from epitaxial growth of a single molecule on a metal surface. Although phase transitions in 2D-atomic systems have been well studied for over 80 years, molecular systems are less well understood due to their larger size and the complex interplay of relatively weak forces that govern the crystalline packing. Three phases of metallated phthalocyanines are studied as a function of substrate temperature and submonolayer coverage. Three phases, the 2D-gas phase, the low temperature commensurate phase, and the high temperature incommensurate phase, are each studied using TPPE and low energy electron diffraction. The image state is found to be an excellent probe of the local crystal structure and local workfunction. Preliminary studies focus on the temperature and coverage dependent energies and intensities of the image state peak in domains of each phase. Temperature dependent studies reveal a pseudo-isosbestic point in the transition from the low temperature commensurate to the high temperature incommensurate phases. Coverage dependence reveals a redshift of the image state with increasing molecular density and decreasing workfunction, and low temperature studies reveal long time scale kinetics of reorganization. Preliminary experimental results are interpreted with the aid of kinetic monte carlo simulations. Further studies will aim to obtain quantitative thermodynamics of these submonolayer coverages. Two photon photoemission spectrscopy has proven to be a powerful tool for understanding basic surface physics of atomic and molecular systems. In particular, the image state has proven to be a powerful probe of the first 1-2 ML coverage of a molecular system. In order to improve the applicability of TPPE to answer device relevant questions, the technique will need to resolve, identify, and characterize molecularly derived bands and excitonic states. The basic selection rules for metal-molecule charge transfer excitations and exciton formation at a surface are understood, but it is not agreed upon whether hot-electrons or interfacial electronic coupling allow for excitations that break normal selection rules. Further, classical dipole quenching is expected to play a strong role in the exciton lifetimes in molecules adsorbed on metal or semiconductor surfaces, though no TPPE study up to this point has been able to observe the expected distance dependent lifteimes. In this final chapter, selection rules and classical dipole quenching are briefly discussed, and general trends are derived for molecular systems adsorbed on highly oriented metal surfaces. Our work up to this point suggests that selection rules are followed rigourously in molecular adsorbates on Ag(111).
Download or read book Probing Metal organic Interfacial Electronic Structure by Two photon Photoemission written by Hanfu Wang and published by . This book was released on 2001 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electronic Structure of the Metal Phthalocyanine Interface Probed by Two Photon Photoemission written by Benjamin William Caplins and published by . This book was released on 2014 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrafast angle-resolved two-photon photoemission (TPPE) is used to probe the electronic structure of highly ordered monolayers of organic materials deposited on the Ag(111) and Ag(100) surfaces. Studies focus on how the electronic states intrinsic to the silver surface are perturbed by the presence of the organic adlayer. These studies show that the strength of the interaction between the surface states and the organic adlayer depends on the nature of the surface state being investigated. For states localized at or near the organic adlayer, substantial changes in the surface state band structure were discovered, whereas for states residing farther in the vacuum the surface state band structure was perturbed surprisingly little. The results presented here give detailed insight into the interaction between the electronic states of organic adlayers and the silver surface.
Download or read book Ultrafast Phenomena XV written by Paul Corkum and published by Springer Science & Business Media. This book was released on 2007-08-15 with total page 853 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the results presented at the 15th International Conference on Ultrafast Phenomena and provides an up-to-date view of this important field. It presents the latest advances in ultrafast science, including both ultrafast optical technology and the study of ultrafast phenomena. It covers picosecond, femtosecond, and attosecond processes relevant to applications in physics, chemistry, biology, and engineering.
Download or read book Time resolved Two photon Photoemission Studies of Electron Dynamics at Metal Surfaces written by Jianming Cao and published by . This book was released on 1996 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Femtosecond Time resovled Two photon Photoemission Studies of Electron Dynamics in Metals written by Giorgio Margaritondo and published by . This book was released on 1997 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photonic Probes of Surfaces written by P. Halevi and published by Newnes. This book was released on 2012-12-02 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is devoted principally to optical spectroscopies of material surfaces and also encompasses scattering techniques and theoretical response analysis as well as spectroscopies. In addition to solid surfaces some attention is also devoted to interfaces between two solids, between a solid and a liquid and to a liquid-vapor interface. These surfaces may be clean and perfect, in which case the purpose of the spectroscopical method at hand is to determine the deviation of the atomic structure in the surface region from that in the bulk, namely the surface reconstruction. Otherwise the surface may be imperfect due to roughness, strain or overlayers, in which case the spectroscopy can yield information on the nature of such imperfections, including the monitoring of growth processes. One of the foremost purposes of surface spectroscopies is to extract information on atomic and molecular adsorbates on solid surfaces. Most of the 10 chapters are concerned with photonic sources of excitation, the respective spectral regions ranging from the far infrared to X-rays. In conclusion this book provides a state-of-the-art review of all major types of photonic probes of surfaces and interfaces and deals with both applications and experiment and theory.
Download or read book Handbook of Spintronics written by Yongbing Xu and published by Springer. This book was released on 2015-10-14 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over two volumes and 1500 pages, the Handbook of Spintronics will cover all aspects of spintronics science and technology, including fundamental physics, materials properties and processing, established and emerging device technology and applications. Comprising 60 chapters from a large international team of leading researchers across academia and industry, the Handbook provides readers with an up-to-date and comprehensive review of this dynamic field of research. The opening chapters focus on the fundamental physical principles of spintronics in metals and semiconductors, including an introduction to spin quantum computing. Materials systems are then considered, with sections on metallic thin films and multilayers, magnetic tunnelling structures, hybrids, magnetic semiconductors and molecular spintronic materials. A separate section reviews the various characterisation methods appropriate to spintronics materials, including STM, spin-polarised photoemission, x-ray diffraction techniques and spin-polarised SEM. The third part of the Handbook contains chapters on the state of the art in device technology and applications, including spin valves, GMR and MTJ devices, MRAM technology, spin transistors and spin logic devices, spin torque devices, spin pumping and spin dynamics and other topics such as spin caloritronics. Each chapter considers the challenges faced by researchers in that area and contains some indications of the direction that future work in the field is likely to take. This reference work will be an essential and long-standing resource for the spintronics community.
Download or read book Book of Abstracts written by and published by . This book was released on 2000 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Molecule Metal Interface written by Norbert Koch and published by John Wiley & Sons. This book was released on 2013-02-08 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviewing recent progress in the fundamental understanding of the molecule-metal interface, this useful addition to the literature focuses on experimental studies and introduces the latest analytical techniques as applied to this interface. The first part covers basic theory and initial principle studies, while the second part introduces readers to photoemission, STM, and synchrotron techniques to examine the atomic structure of the interfaces. The third part presents photoelectron spectroscopy, high-resolution UV photoelectron spectroscopy and electron spin resonance to study the electronic structure of the molecule-metal interface. In the closing chapter the editors discuss future perspectives. Written as a senior graduate or senior undergraduate textbook for students in physics, chemistry, materials science or engineering, the book's interdisciplinary approach makes it equally relevant for researchers working in the field of organic and molecular electronics.
Download or read book Spectroscopy of Complex Oxide Interfaces written by Claudia Cancellieri and published by Springer. This book was released on 2018-04-09 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the most recent and compelling experimental results for complex oxide interfaces. The results of this book were obtained with the cutting-edge photoemission technique at highest energy resolution. Due to their fascinating properties for new-generation electronic devices and the challenge of investigating buried regions, the book chiefly focuses on complex oxide interfaces. The crucial feature of exploring buried interfaces is the use of soft X-ray angle-resolved photoemission spectroscopy (ARPES) operating on the energy range of a few hundred eV to increase the photoelectron mean free path, enabling the photons to penetrate through the top layers – in contrast to conventional ultraviolet (UV)-ARPES techniques. The results presented here, achieved by different research groups around the world, are summarized in a clearly structured way and discussed in comparison with other photoemission spectroscopy techniques and other oxide materials. They are complemented and supported by the most recent theoretical calculations as well as results of complementary experimental techniques including electron transport and inelastic resonant X-ray scattering.
Download or read book Proceedings of the 11th International Conference on Vacuum Ultraviolet Radiation Physics written by T. Miyahara and published by Elsevier. This book was released on 2012-12-02 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: These volumes contain 365 of the 505 papers presented at the VUV-11 Conference, held at Rikkyo University, Tokyo, from August 27th to September 1st 1995. The papers are divided into three sections: atomic and molecular spectroscopy, solid state spectroscopy and instrumentation and technological applications. New aspects presented were both quantitative and qualitative improvements in fluorescence spectroscopy and magnetic circular dichroism measurements. The fluorescence data are complementary to those of photoemission in a sense but they appear to open up a new method to analyze the optical excitation and relaxation processes. The application of magnetic circular dichroism has proved to be useful not only in analyzing the electronic structures of magnetic materials but also in practical applications to material engineering as found in experiments combined with photoelectron microscopy. Excellent developments in applications are only found in the field of surface photochemistry, where the technique of etching using VUV light has been appreciably refined. Although the majority of distinctive scientific features in the VUV-11 Conference have been brought about by the application of synchrotron radiation, experiments using a different type of light source appear to have progressed steadily. This is evident in the studies of plasma radiation.
Download or read book Encyclopedia of Interfacial Chemistry written by and published by Elsevier. This book was released on 2018-03-29 with total page 5276 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
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 Hard X ray Photoelectron Spectroscopy HAXPES written by Joseph Woicik and published by Springer. This book was released on 2015-12-26 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides the first complete and up-to-date summary of the state of the art in HAXPES and motivates readers to harness its powerful capabilities in their own research. The chapters are written by experts. They include historical work, modern instrumentation, theory and applications. This book spans from physics to chemistry and materials science and engineering. In consideration of the rapid development of the technique, several chapters include highlights illustrating future opportunities as well.
Download or read book Modern Techniques of Surface Science written by D. P. Woodruff and published by Cambridge University Press. This book was released on 1994-03-03 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Revised and expanded second edition of the standard work on new techniques for studying solid surfaces.
Download or read book Fundamentals of Sum Frequency Spectroscopy written by Y. R. Shen and published by Cambridge University Press. This book was released on 2016-02-18 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book on the topic, and written by the founder of the technique, this comprehensive resource provides a detailed overview of sum-frequency spectroscopy, its fundamental principles, and the wide range of applications for surfaces, interfaces, and bulk. Beginning with an overview of the historical context, and introductions to the basic theory of nonlinear optics and surface sum-frequency generation, topics covered include discussion of different experimental arrangements adopted by researchers, notes on proper data analysis, an up-to-date survey commenting on the wide range of successful applications of the tool, and a valuable insight into current unsolved problems and potential areas to be explored in the future. With the addition of chapter appendices that offer the opportunity for more in-depth theoretical discussion, this is an essential resource that integrates all aspects of the subject and is ideal for anyone using, or interested in using, sum-frequency spectroscopy.
