Multiple Electron Processes In Fast Ion Atom Collisions

Research in atomic physics at the Lawrence Berkeley Laboratory Super-HILAC and Bevalac accelerators on multiple-electron processes in fast ion-atom collisions is described. Experiments have studied various aspects of the charge-transfer, ionization, and excitation processes. Examples of processes in which electron correlation plays a role are resonant transfer and excitation and Auger-electron emission. Processes in which electron behavior can generally be described as uncorrelated include ionization and charge transfer in high-energy ion-atom collisions. A variety of experiments and results for energies from 1 MeV/u to 420 MeV/u are presented. 20 refs., 15 figs.

The principal goal of this book is to provide state-of-the-art coverage of the non-relativistic three- and four-body theories at intermediate and high energy ion-atom and ion-molecule collisions. The focus is on the most frequently studied processes: electron capture, ionization, transfer excitation and transfer ionization. The content is suitable both for graduate students and experienced researchers. For these collisions, the literature has seen enormous renewal of activity in the development and applications of quantum-mechanical theories. This subject is of relevance in several branches of science and technology, like accelerator-based physics, the search for new sources of energy and high temperature fusion of light ions. Other important applications are in life sciences via medicine, where high-energy ion beams are used in radiotherapy for which a number of storage ring accelerators are in full operation, under construction or planned to be built worldwide. Therefore, it is necessary to review this field for its most recent advances with an emphasis on the prospects for multidisciplinary applications.This book is accompanied by Interdisciplinary Research on Particle Collisions and Quantitative Spectroscopy Volume 2 - Fast Collisions of Light Ions with Matter: Charge Exchange and Ionization.

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.

Two-electron capture and loss processes have been investigated for highly charged ions colliding with gas targets in the energy range 0.5 to 9.0 MeV/u. Ionic species used for projectiles were S(13+), Ar(15+), Ca(12-19+), and V(18-22+); target gases used were H2, He, and Ne. Double-electron capture decreases very rapidly with increasing beam energy, and the cross sections are typically 1 to 2 orders of magnitude smaller than the single-electron capture cross sections over the energy range studied. Loss of two projectile electrons varies with the beam energy and charge state, and depends strongly on whether L- or K-shell electrons are removed. 11 refs., 3 figs.

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.

One of the Top Selling Physics Books according to YBP Library Services Suitable for graduate students, experienced researchers, and experts, this book provides a state-of-the-art review of the non-relativistic theory of high-energy ion-atom collisions. Special attention is paid to four-body interactive dynamics through the most important theoretical methods available to date by critically analyzing their foundation and practical usefulness relative to virtually all the relevant experimental data. Fast ion-atom collisions are of paramount importance in many high-priority branches of science and technology, including accelerator-based physics, the search for new sources of energy, controlled thermonuclear fusion, plasma research, the earth's environment, space research, particle transport physics, therapy of cancer patients by heavy ions, and more. These interdisciplinary fields are in need of knowledge about many cross sections and collisional rates for the analyzed fast ion-atom collisions, such as single ionization, excitation, charge exchange, and various combinations thereof. These include two-electron transitions, such as double ionization, excitation, or capture, as well as simultaneous electron transfer and ionization or excitation and the like--all of which are analyzed in depth in this book. Quantum Theory of High-Energy Ion-Atom Collisions focuses on multifaceted mechanisms of collisional phenomena with heavy ions and atoms at non-relativistic high energies.

This thesis presents a non perturbative theory to describe multi-electronic processes occurring in the course of ion-atom collisions. The treatment is semiclassical in that the relative target-projectile motion is described by classical straight-line constant velocity trajectories, while the electronic dynamics is treated quantum mechanically, by solving non perturbatively the time-dependent Schödinger equation. The treatment has been implemented in a new version of two-active-electron computer code. Besides the long and complex development and tests of the code, the last three years have been especially devoted to understanding of the physics of specific heavy particle scattering events. We have undertaken the study of three collision systems with various features: (i) low charge ion-ion collisions with an extreme importance of electronic correlation (H+ + H- collisions), (ii) multiply charged projectile-atom collisions (C4+ + He) and (iii) He+ + He collisions with the dynamical treatment of the three electrons. Our guideline was always to target systems for which experimental and theoretical results were available (at least in some energy domain), with still open questions, related, for example, to strong disagreement between the various data. We have tried as much as our computing resources and allowed it to produce results with controlled convergence. These investigations were carried out in a very wide, up to three decades, energy domain with same collision description (i.e. same basis sets), which brought continuity and coherence on the predictions and the interpretations of the results and of the underlying mechanisms giving rise to the processes considered.

This graduate/research level text introduces the theory of multi-electron transitions in atomic, molecular and optical physics, emphasizing the emerging topic of dynamic electron correlation. The book begins with an overview of simple binomial probabilities, classical scattering theory, quantum scattering and correlation, followed by the theory of single electron transition probabilities. Multiple electron transition probabilities are then treated in detail. Various approaches to multiple electron transitions are covered including the independent electron approximation, useful statistical methods and perturbation expansions treating correlation in both weak and strong limits. The dynamics of electron correlation are strongly emphasized. The text contains a comprehensive summary of data for few and many-electron transitions in atoms and molecules, including transitions on different atomic centers, fast ion-atom and electron-atom interactions, and recent observations using synchrotron radiation. Emphasis is given to methods that may be used by nonspecialists.