Ionization And Electron Emission Of Heavy Ion Atom Collisions

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.

High-energy ion-atom collisions are subject of intense investigation in present-day atomic physics. They give fundamental information on the collision mechanism of ions and atoms, and on their highly excited states. This book includes invited survey talks, and invited contributions, all carefully refereed. The topics covered are electron capture and loss (including ionization), double electron and resonance processes, electron correlation and post-collision interaction effects, collisions of antiparticles with atoms, and so forth.

This book is based upon a part of the invited and contributing talks at the 25th International Symposium on Ion-Atom Collisions, ISIAC (biennial), held on July 23-25, 2017 in Palm Cove, Queensland, Australia. To aid the general reader, all the authors tried to present their chapters in the context of the development of the addressed particular themes and the underlying major ideas and intricacies. Some chapters contain new results that have not been previously published elsewhere. Whenever possible, the authors made their attempts to connect the basic research in atomic and molecular collision physics with some important applications in other branches of physics as well as across the physics borders. It is hoped that the material presented in this book will be interesting and useful to the beginners and specialists alike. The contents and expositions are deemed to be helpful to the beginners in assessing the potential overlap of some of the presented material with their own research themes and this might provide motivations for possible further upgrades. Likewise, specialists could take advantage of these reviews to see where the addressed themes were and where they are going, in order to acknowledge the fruits of the efforts made thus far and actively contribute to tailoring the directions of future research. Overall, this book is truly interdisciplinary. It judiciously combines experiments and theories within particle collision physics on atomic and molecular levels. It presents state-of-the-art fundamental research in this field. It addresses the possibilities for significant and versatile applications outside standard atomic and molecular collision physics ranging from astrophysics, surface as well as cluster physics/chemistry, hadron therapy in medicine and to the chemical industry. It is then, as Volume 2, fully in the spirit of the 'Aims and Scope' of this book series by reference to its 'Mission Statement'.

The systematics of differential ionization cross sections are explored for incident charged particles which possess atomic structure. Although little has been published regarding outer shell ionization by structured projectiles, sufficient data are becoming available to provide some insight into the collision process. This discussion concentrates on systematics of emission cross sections for the intermediate and high energy projectiles where the applicability of high energy approximations can be tested and the dramatic changes in emission spectra observed as the projectile energies decrease. Since heavy ion interactions are important in many research fields, it is particularly useful to determine where simple methods of cross section scaling may be appropriate.

These proceedings give fundamental information on the collision mechanisms of ions and atoms at relatively high energies and on their highly excited atomic states. The information derived from such studies can often be applied in other fields such as material analysis, dosimetry, the study of the upper atmosphere and controlled fusion. Phenomena involving the classical ion-atom collision fields, impact parameter dependences, quasimolecular and electron correlation effects, coherence phenomena, the electron and photon spectroscopy of highly charged projectile and recoil ions, the loss and capture of electrons, molecular and solid state effects, and different aspects of instrumentation are all discussed in this volume.

The last decade has seen dramatic progress in the development of devices for producing mu1ticharged ions. Indeed it is now pos sible to produce any charge state of any ion right up through 92 fully-stripped uranium (U +). Equally dramatic progress has been achieved in the energy range of the available ions. As an example, fully-stripped neon ions have been produced in useable quantities with kinetic energies ranging from a few ev to more than 20 Gev. Interest in the atomic physics of multicharged ions has grown apace. In the fusion program, the spectra of these ions is an im portant diagnostic tool. Moreover the presence of mu1ticharged ions presents a serious energy loss mechanism in fusion devices. This fact has motivated a program to study the collision mech anisms involved. In another area, mu1ticharged ions are present in the solar corona and the interstellar medium and knowledge of their collision properties and spectra is essential to understand ing the astrophysics. Other possible applications are to x-ray lasers and heavy ion inertial fusion. On a more fundamental level, new possibilities for testing quantum electrodynamics with mu1ti charged ions have emerged.

Atomic collisions offer some unique opportunities to study atomic structure and reaction mechanisms in experiment and theory, especially for projectiles of high atomic number provided by modern accelerators. The book is meant as an introduction into the field and provides some basic theoretical understanding of the atomic processes occurring when a projectile hits another atom. It also furnishes the tools for a mathematical description, however, without going deeper into the technical details, which can be found in the literature given. With this aim, the focus is on reactions, in which only a single active electron participates. Collisional excitation, ionization and charge transfer are discussed for collision velocities ranging from slow to comparable to the speed of light. For the highest projectile velocities, energy can be converted into mass, so that electron-positron pairs are created. In addition to the systematic treatment, a theoretical section specializes on electron-electron correlations and three chapters are devoted to selected highlights bordering to surface science and to physics with antiprotons. * Simple access to the theory of collisions between ions and atoms * Systematic treatment of basic features needed for an understanding * Mathematical details are omitted and referred to references * In order to bear out the essential ideas most clearly, a single active electron is assumed in most cases * In selected examples, theoretical results are confronted with experiment * Discussion supported by a large number of illustrations * Selected highlights in borderline fields are presented

This book collects the papers presented at the NATO Advanced Research Workshop on "Ionization of Solids by Heavy Particles", held in Giardini-Naxos (Taormina), Italy, on June 1 -5, 1992. The meeting was the first to gather scientists to discuss the physics of electron emission and other ionization effects occurring during the interaction of heavy particles with condensed matter. The central problem in the field is how to use observations of electron emission and final radiation damage to understand what happens inside the solid, like excitation mechanisms, the propagation of the electronic excitation along different pathways, and surface effects. The ARW began with a brief survey of the field, stressing the unknowns. It was pointed out that ionization theories can only address the very particular case of weak perturbations. For this problem, this meant high speed, low-charged projectiles (a perturbation treatment of interactions with slow, highly charged ions was later presented). Only semi-empirical models exist for velocities lower than the Fermi velocity in the solid, which can be used to predict kinetic electron emission yields. These models, however, do not address the basic questions about the mechanisms for electron excitation, transport and escape through the surface layer.