Download or read book On the Role of Projectile Electrons in an Independent Electron Model Description of Dressed Ion Impact on Atoms written by Gerald Schenk and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The presence of electrons on ions which collide with neutral atoms constitutes a challenge to theoretical descriptions of the collision dynamics. These collisions pose quantum-mechanical many-body problems that cannot be fully solved; one has to resort to approximations, such as the independent electron model (IEM), in which the N-electron problem is reduced to N single-electron problems. The time-development of a given electron is governed by the nuclear Coulomb potentials and an electronic mean-field potential formed by the other electrons. This framework is used in the present work to explore the active role of projectile electrons in collisions of dressed boron- and carbon-ions with neon atoms, as well as the seemingly simple HeHe collision system. In the present IEM description the collision problem is expressed in the form of time-dependent Schrdinger equations with a common single-electron Hamiltonian. The single-electron equations are solved numerically with a two-centre basis expansion method in which the continuum is represented by dynamically generated basis states. From these calculations single-electron transition amplitudes are obtained and many-electron quantities are computed with different statistical final-state analyses, which do or do not respect the Pauli exclusion principle. In BNe collisions transfer ionization processes that involve electrons at both centres were found to contribute to target multiple ionization coincident with an unchanged projectile charge state. Total cross sections for collision channels where the projectile charge state is changed are presented for BNe and CNe collisions. The present method reliably provides total cross sections for most collision channels, except for the loss of projectile electrons. The contributions of these collision channels to the net recoil ion production are investigated. These results are compared with those for collisions of equicharged bare helium and lithium ions with neon. In a modification of the present approach a piecewise definition of the common Hamiltonian is proposed. It ensures the correct asymptotic behaviour of the mean-field potential at large internuclear distances before the collision for active electrons of both centres. The model is applied to the HeHe collision system and compared with the (unmodified) present approach.

Download or read book Electron Emission in Heavy Ion Atom Collisions written by Nikolaus Stolterfoht and published by Springer Science & Business Media. This book was released on 1997-10-28 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reviews the theoretical and experimental work about continuous electron emission in energetic ion-atom collisions over the last 30 years. General properties of the two-center electron emission are analyzed, and particular attention is given to screening effects. The book also offers an overview of multiple ionization processes.

Download or read book Electron Emission in Heavy Ion Atom Collisions written by Nikolaus Stolterfoht and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron EM reviews the theoretical and experimental work of the last 30 years on continuous electron emission in energetic ion-atom collisions. High incident energies for which the projectile is faster than the mean orbital velocity of the active electron are considered. Emphasis is placed on the interpretation of ionization mechanisms. They are interpreted in terms of Coulomb centers associated with the projectile and target nuclear fields which strongly interact with the outgoing electron. General properties of the two-center electron emission are analyzed. Particular attention is given to screening effects. A brief overview of multiple ionization processes is also presented. The survey concludes with a complete compilation of experimental studies of ionization cross sections.

Download or read book Nonequilibrium Effects in Ion and Electron Transport written by Jean W. Gallagher and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the contributions of the participants in the Sixth International Swarm Seminar, held August 2-5, 1989, at the Webb Institute in Glen Cove, New York. The Swarm Seminars are traditionally held as relatively small satellite conferences of the International Conference on the Physics of Electronic and Atomic Collisions (ICPEAC) which occurs every two years. The 1989 ICPEAC took place in New York City prior to the Swarm Seminar. The focus of the Swarm Seminars has been on basic research relevant to understanding the transport of charged particles, mainly electrons and ions, in weakly ionized gases. This is a field that tends to bridge the gap between studies of fundamental binary atomic and molecular collision processes and studies of electrical breakdown or discharge phenomena in gases. Topics included in the 1989 seminar ranged the gamut from direct determinations of charged-particle collision cross sections to use of cross sections and swarm parameters to model the behavior of electrical gas discharges. Although the range of subjects covered was in many respects similar to that of previous seminars, there was an emphasis on certain selected themes that tended to give this seminar a distinctly different flavor. There was, for example, considerable discussion on the meaning of "equilibrium" and the conditions under which nonequilibrium effects become important in the transport of electrons through a gas.

Download or read book Forward Electron Production in Heavy Ion atom and Ion solid Collisions written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A sharp cusp in the velocity spectrum of electrons, ejected in ion-atom and ion-solid collisions, is observed when the ejected electron velocity vector v/sub e/ matches that of the emergent ion vector v/sub p/ in both speed and direction. In ion-atom collisions, the electrons originate from capture to low-lying, projectile-centered continuum states (ECC) for fast bare or nearly bare projectiles, and from loss to those low-lying continuum states (ELC) when loosely bound projectile electrons are available. Most investigators now agree that ECC cusps are strongly skewed toward lower velocities, and exhibit full widths half maxima roughly proportional to v/sub p/ (neglecting target-shell effects, which are sometimes strong). A close examination of recent ELC data shows that ELC cusps are instead nearly symmetric, with widths nearly independent on v/sub p/ in the velocity range 6 to 18 a.u., a result only recently predicted by theory. Convoy electron cusps produced in heavy ion-solid collisions at MeV/u energies exhibit approximately velocity-independent widths very similar to ELC cusp widths. While the shape of the convoy peaks is approximately independent of projectile Z, velocity, and of target material, it is found that the yields in polycrystalline targets exhibit a strong dependence on projectile Z and velocity. While attempts have been made to link convoy electron production to binary ECC or ELC processes, sometimes at the last layer, or alternatively to a solid-state wake-riding model, our measured dependences of cusp shape and yield on projectile charge state and energy are inconsistent with the predictions of available theories. 10 references, 8 figures, 1 table.

Download or read book Atomic Processes in Electron Ion and Ion Ion Collisions written by F. Brouillard and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 495 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four years after a first meeting in BADDECK, Canada, on the Physics of Ion-Ion and Electron-Ion collisions, a second Nato Advanced Study Institute, in HAl~/Lesse, Belgium, reexamined the subject which had become almost a new one, in consideration of the many important developments that had occured in the mean time. The developments have been particularly impressive in two areas : the di-electronic recombination of electrons with ions and the collisional processes of mUltiply charged ions. For dielectronic recombination, a major event was the obtainment, in 1983, of the first experimental data. This provided, at last, a non speculative basis for the study of that intricate and subtle process and strongly stimulated the theoretical activities. Multiply charged ions, on the other hand, have become popular, thanks to the development of powerful ion sources. This circumstance, together with a pressing demand from thermonuclear research for ionisation and charge exchange cross sections, has triggered systematic experimental investigations and new theoretical studies, which have contributed to considerably enlarge, over the last five years, our understanding of the collisional processes of multiply charged ions. Dielectronic recombination and multiply charged ions were therefore central points in the programme of the A.S.I. in HAN/Lesse and are given a corresponding emphasis in the present book.

Download or read book Theory of Electron Atom Collisions written by Philip G. Burke and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors aim to hone the theory of electron-atom and electron-ion collisions by developing mathematical equations and comparing their results to the wealth of recent experimental data. This first of three parts focuses on potential scattering, and will serve as an introduction to many of the concepts covered in Parts II and III. As these processes occur in so many of the physical sciences, researchers in astrophysics, atmospheric physics, plasma physics, and laser physics will all benefit from the monograph.

Download or read book Comparison of Convoy Electron Production in Ion atom and Ion solid Collisions written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We begin with an overview for the benefit of participants lacking acquaintance with the subject of convoy-electron production, and continue with highlights of developments occurring since a review and a comprehensive article published in 1982. A sharp cusp in the velocity spectrum of electrons, ejected in ion-atom and ion-solid collisions, is observed when the ejected electron velocity vector v/sub e/ matches that of the emergent ion vector v in both speed and direction. In ion-atom collisions, the electrons primarily originate from capture to low-lying projectile-centered continuum states (ECC) for fast bare or nearly bare projectiles, and primarily from loss to low-lying continuum states (ELC) when loosely bound projectile electrons are available. Most investigators now agree that ECC cusps are strongly skewed toward lower velocities and exhibit full widths half maxima roughly proportional to v (neglecting sometimes strong shell effects). Convoy cusps produced in heavy ion-solid collisions at MeV/u energies are slightly skewed toward high electron velocities, but exhibit velocity-independent widths, very similar to ELC cusp widths. While the shape of the convoy peaks is approximately independent of projectile Z, velocity, and target, dependence on projectile Z as Z2 7 and energy as E−2 2. Attempts have been made to link convoy electron production to binary ECC or ELC processes, sometimes at the last layer, or alternatively to a solid-state wake-riding model, but our measured dependences of cusp shape and yield on heavy projectile charge state q and energy are inconsistent with available theories. These wake-riding theories seek to explain the origin of convoy electrons in terms of electrons trapped into an oscillatory electron density polarization potential trailing each projectile, which are then liberated at the surface.

Download or read book Electron Impact Phenomena written by F. H. Field and published by Academic Press. This book was released on 2013-10-22 with total page 577 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron Impact Phenomena and the Properties of Gaseous Ions, Revised Edition deals with data pertaining to electron impact and to molecular gaseous ionic phenomena. This book discusses electron impact phenomena in gases at low pressure that involve low-energy electrons, which result in ion formation. The text also describes the use of mass spectrometers in electron impact studies and the degree of accuracy obtained when measuring electron impact energies. This book also reviews relatively low speed electrons and the transitions that result in the ionization of the atomic system. This text then discusses diatomic molecules whose mass spectra can be interpreted using the Franck-Condon principle. This selection also presents some examples of ions in solution that resemble the gaseous ions formed by electron impacts. The energies of these gaseous ions can be the key to understanding the mechanisms of ionic reactions. These examples include the olefin addition reactions and catalytic cracking. This text will prove invaluable for research chemists, students, and professors in chemistry and related fields such as organic chemistry and electrochemistry.

Download or read book Trapping Highly Charged Ions written by John Gillaspy and published by Nova Publishers. This book was released on 2001 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides and elementary introduction to the field of trapping highly charged ions. The first group of chapters is intended to describe the various sorts of highly charged ion traps: EBIT, EBIS, ECR, Storage Rings and various speciality traps. The authors focus on their own ion trap facilities in order to teach by example. The chapters range in scope from comprehensive reviews to brief introductions. The second group of chapters is intended to give a flavour of the various sorts of scientific research which are presently being carried out with traps for highly charged ions. These chapters not only inform, but also stimulate newcomers to think up fresh ideas. The articles in this second group generally fall into one of three broad categories: atomic structure experiments, ion-surface interactions and precision mass spectrometry. The third group of chapters is intended to deal with theory and spectroscopic analysis. It provides some of the background material necessary to make sense of observed phenomenology, to allow detailed explanation of experimental data, and to sensibly plan further experimentation. An appendix provides a complete keyword-annotated bibliography of pa

Download or read book Collisions of Electrons with Atoms and Molecules written by G.F. Drukarev and published by Springer. This book was released on 1987-09-30 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a short outline of the present state of the theory of electron collisions with atomic particles - atoms, molecules and ions. It is addressed to those who by nature of their work need detailed information about the cross sections of various processes of electron collisions with atomic particles: experimentalists working in plasma physics, optics, quantum electronics, atmospheric and space physics, 'etc. Some of the cross sections have been measured. But in many important cases the only source of information is theoretical calcu lation. The numerous theoretical papers dealing with electronic collision processes contain various approximations. The inter relation between them and the level of their accuracy is often diffi cult to understand without a systematic study of the theory of atomic collisions, not to mention that theoretical considerations are necessary for the consistent interpretation of experimental results. The main constituents of the book are: 1. General theory with special emphasis on the topics most impor tant for understanding and discussing electron collisions with atomic particles.

Download or read book INIS Atomindex written by and published by . This book was released on 1996 with total page 794 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Newly Appreciated Roles for Electrons in Ion atom Collisions written by and published by . This book was released on 1990 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the previous Debrecen workshop on High-Energy Ion-Atom Collisions there have been numerous experiments and substantial theoretical developments in the fields of fast ion-atom and ion- solid collisions concerned with explicating the previously largely underappreciated role of electrons as ionizing and exciting agents in such collisions. Examples to be discussed include the double electron ionization problem in He; transfer ionization by protons in He; double excitation in He; backward scattering of electrons in He; the role of electron-electron interaction in determining beta parameters for ELC; projectile K ionization by target electrons; electron spin exchange in transfer excitation; electron impact ionization in crystal channels; resonant coherent excitation in crystal channels; excitation and dielectronic recombination in crystal channels; resonant transfer and excitation; the similarity of recoil ion spectra observed in coincidence with electron capture vs. electron loss; and new research on ion-atom collisions at relativistic energies.

Download or read book Nonequilibrium Effects in Ion and Electron Transport written by and published by . This book was released on 1990 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the contributions of the participants in the Sixth International Swarm Seminar, held August 2-5, 1989, at the Webb Institute in Glenn Cove, New York. The Swarm Seminars are traditionally held as relatively small satellite conferences of the International Conference on the Physics of Electronic and Atomic Collisions (ICPEAC) which occurs every two years. The 1989 ICPEAC took place in New York City prior to the Swarm Seminar. The focus of the Swarm Seminars has been on basic research relevant to understanding the transport of charged particles, mainly electrons and ions, in weakly ionized gases. This field that tends to bridge the gap between studies of fundamental binary atomic and molecular collision processes and studies of electrical breakdown or discharge phenomena in gases. Topics includes in the 1989 seminar ranged the gamut from direct determinations of charged-particle collision cross sections to use of cross sections and swarm parameters to model the behavior of electrical gas discharges. The range of subjects covered was in many respects similar to that of previous seminars. (js).

Download or read book Particle Induced Electron Emission II written by Dietmar Hasselkamp and published by Springer. This book was released on 1992 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron emission is a fundamental phenomenon which accompanies most interactions of energetic particles with solid surfaces. Not only is it a special effect which for almost ninety years has attracted the interest of physicists, but it is also of acute importance in such fields as radiation effects and transport phenomena in solids (e.g., radiation biology), plasma-surface interactions, microtechnology, surface analysis, ion microscopies, particle detector development and others. While Volume I emphasizes the theoretical description of the mechanisms of electron emission, this volume reviews modern experimental trends and aspects of the phenomenon, e.g., kinetic electron emission from massive solids and from thin foils under bombardment with positive, negative, and neutral particles, and the measurement of electron statistics in connection with potential and kinetic emission due to slow singly and multiply charged projectiles.

Download or read book Electron and Photon Interactions with Atoms written by Hans Kleinpoppen and published by Plenum Publishing Corporation. This book was released on 1976 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: