Variational Methods in Electron-Atom Scattering Theory


Book Description

The investigation of scattering phenomena is a major theme of modern physics. A scattered particle provides a dynamical probe of the target system. The practical problem of interest here is the scattering of a low energy electron by an N-electron atom. It has been difficult in this area of study to achieve theoretical results that are even qualitatively correct, yet quantitative accuracy is often needed as an adjunct to experiment. The present book describes a quantitative theoretical method, or class of methods, that has been applied effectively to this problem. Quantum mechanical theory relevant to the scattering of an electron by an N-electron atom, which may gain or lose energy in the process, is summarized in Chapter 1. The variational theory itself is presented in Chapter 2, both as currently used and in forms that may facilitate future applications. The theory of multichannel resonance and threshold effects, which provide a rich structure to observed electron-atom scattering data, is presented in Chapter 3. Practical details of the computational implementation of the variational theory are given in Chapter 4. Chapters 5 and 6 summarize recent appli cations of the variational theory to problems of experimental interest, with many examples of the successful interpretation of complex structural fea tures observed in scattering experiments, and of the quantitative prediction of details of electron-atom scattering phenomena.




Atomic-Molecular Ionization by Electron Scattering


Book Description

Covers quantum scattering theories, experimental and theoretical calculations and applications in a comprehensive manner.




Electron Scattering: Theory & Applications


Book Description

A balanced and comprehensive account is given here of the electron-atom-molecule scattering calculations carried out by the author. The topic is of great interest owing to many-fold relevance e.g. in the planetary and outer space environments. Collisions of electrons with atoms and molecules provide a unique diagnostic probe of the fundamental interactions of atomic-molecular systems and are the basic physical processes that determine the behavior of ionized gases. To understand and to predict quantitatively the behavior of ionized gases found in planetary environments etc, requires development of theory of electron collisions along with mathematical and computational tools that enable reliable calculations of the different collision parameters. The present book signifies our sincere efforts towards electron-atom-molecule scattering: theory and scattering cross section calculations. The derived scattering cross sections can be utilized to carry out variety of parameters. The applications of these cross sections in the planetary atmospheres and outer space environments have been discussed in the next volume of this book series.




Elastic and Inelastic Scattering in Electron Diffraction and Imaging


Book Description

Elastic and inelastic scattering in transmission electron microscopy (TEM) are important research subjects. For a long time, I have wished to systematically summarize various dynamic theories associated with quantitative electron micros copy and their applications in simulations of electron diffraction patterns and images. This wish now becomes reality. The aim of this book is to explore the physics in electron diffraction and imaging and related applications for materials characterizations. Particular emphasis is placed on diffraction and imaging of inelastically scattered electrons, which, I believe, have not been discussed exten sively in existing books. This book assumes that readers have some preknowledge of electron microscopy, electron diffraction, and quantum mechanics. I anticipate that this book will be a guide to approaching phenomena observed in electron microscopy from the prospects of diffraction physics. The SI units are employed throughout the book except for angstrom (A), which is used occasionally for convenience. To reduce the number of symbols used, the Fourier transform of a real-space function P'(r), for example, is denoted by the same symbol P'(u) in reciprocal space except that r is replaced by u. Upper and lower limits of an integral in the book are (-co, co) unless otherwise specified. The (-co, co) integral limits are usually omitted in a mathematical expression for simplification. I very much appreciate opportunity of working with Drs. J. M. Cowley and J. C. H. Spence (Arizona State University), J.




Scattering Theory of Molecules, Atoms and Nuclei


Book Description

The aim of the book is to give a coherent and comprehensive account of quantum scattering theory with applications to atomic, molecular and nuclear systems. The motivation for this is to supply the necessary theoretical tools to calculate scattering observables of these many-body systems. Concepts which are seemingly different for atomic/molecular scattering from those of nuclear systems, are shown to be the same once physical units such as energy and length are diligently clarified. Many-body resonances excited in nuclear systems are the same as those in atomic systems and come under the name of Feshbach resonances. We also lean heavily on semi-classical methods to explain the physics of quantum scattering OCo especially the interference seen in the angle dependence of the cross section. Having in mind a wide readership, the book includes sections on scattering in two dimensions which is of use in surface physics. Several problems are also included at the end of each of the chapters.




Fundamentals of Inelastic Electron Scattering


Book Description

Electron energy loss spectroscopy (ELS) is a vast subject with a long and honorable history. The problem of stopping power for high energy particles interested the earliest pioneers of quantum mechanics such as Bohr and Bethe, who laid the theoretical foun dations of the subject. The experimental origins might perhaps be traced to the original Franck-Hertz experiment. The modern field includes topics as diverse as low energy reflection electron energy loss studies of surface vibrational modes, the spectroscopy of gases and the modern theory of plasmon excitation in crystals. For the study of ELS in electron microscopy, several historically distinct areas of physics are relevant, including the theory of the Debye Waller factor for virtual inelastic scattering, the use of complex optical potentials, lattice dynamics for crystalline specimens and the theory of atomic ionisation for isolated atoms. However the field of electron energy loss spectroscopy contains few useful texts which can be recommended for students. With the recent appearance of Raether's and Egerton's hooks (see text for references), we have for the first time both a comprehensive review text-due to Raether-and a lucid introductory text which emphasizes experimental aspects-due to Egerton. Raether's text tends to emphasize the recent work on surface plasmons, while the strength of Egerton's book is its treatment of inner shell excitations for microanalysis, based on the use of atomic wavefunctions for crystal electrons.




Quantum Theory of Scattering


Book Description

This volume addresses the broad formal aspects and applications of the quantum theory of scattering in atomic and nuclear collisions. An encyclopedic source of pioneering work, it serves as a text for students and a reference for professionals in the fields of chemistry, physics, and astrophysics. The self-contained treatment begins with the general theory of scattering of a particle by a central field. Subsequent chapters explore particle scattering by a non-central field, collisions between composite particles, the time-dependent theory of scattering, and nuclear reactions. An examination of dispersion relations concludes the text. Numerous graphs, tables, and footnotes illuminate each chapter, in addition to helpful appendixes and bibliographies.







Low-Energy Electron Scattering from Molecules, Biomolecules and Surfaces


Book Description

Since the turn of the 21st century, the field of electron molecule collisions has undergone a renaissance. The importance of such collisions in applications from radiation chemistry to astrochemistry has flowered, and their role in industrial processes such as plasma technology and lighting are vital to the advancement of next generation devices. F




Multiple Scattering Theory


Book Description

In 1947, it was discovered that multiple scattering theory (MST) can be used to solve the Schröedinger equation for the stationary states of electrons in a solid. Written by experts in the field, J S Faulkner, G Malcolm Stocks and Yang Wang, this book collates the results of numerous studies in the field of MST and provides a comprehensive, systematic approach to it. For many scientists, students and engineers working with multiple scattering programmes, this will be a useful guide to help expand the existing knowledge of MST as well as understanding its future implications.