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 Convoy Electron Production by Heavy Ions in Solids written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The term convoy electron refers to those electrons ejected in fast ion-atom and ion-solid collisions closely matched in vector velocity to that of the incident heavy particles responsible for their ejection. Similarities and differences among electrons ejected into such states through binary electron capture to continuum and electron loss to continuum processes in single ion-atom encounters are compared and contrasted to more complex ejection processes occurring in solid targets. Puzzles posed by the apparent strong projectile Z dependence but weak emergent ion charge dependence of the yield in the case of solid targets are reviewed. Very recent progress in resolving these puzzles has been made by recent observations that the apparent mean free path for electron scattering out of the forward direction within the target is observed to be an order of magnitude greater than that for free electrons of equal velocity provided the projectile charge is high. 13 references, 2 figures, 1 table.
Download or read book Convoy Electron Production in Heavy ion solid Collisions written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The properties of the sharp v vector/sub e/ approx. = v vector cusps observed in the velocity spectrum of convoy electrons (v vector/sub e/) ejected in heavy ion-solid collisions in the ion velocity range (v vector) 6 to 18 au are compared to the properties of analogous cusps observed in binary electron capture to the continuum (ECC) and electron loss to the continuum (ELC) collisions in gases. Apart from a skew toward v vector/sub e/> v vector, the v-independent convoy distributions observed are very similar to those for ELC and the cusp widths are the same in both cases. While the shape of convoy peaks is approximately independent of projectile Z, v, and of target material, yields in polycrystalline targets (C, Al, Ag, Au) exhibit a strong dependence on Z and v. Coincidence experiments in which convoy electrons are allocated according to emergent ion charge-state q/sub e/ show a surprising independence of q/sub e/, mirroring the unweighted statistical emergent charge-state fraction. Coincidence experiments of O/sup 6 +/ /sup 7 +/ /sup 8 +/ ions traversing 110 and 100 channels in Au show a strong yield suppression and a dependence of yield on the channel chosen. Interpretation of these observations, comparisons to convoy production studies using protons, and a discussion of remaining puzzles is given. The history of ECC, ELC, and wake-riding models of convoy electron production is also reviewed.
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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Convoy Electrons written by and published by . This book was released on 1990 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent developments in the theory of the production and of the transport of convoy electrons through solids are reviewed. Similarities and differences to cusp electron emission in binary ion-atom collisions and to transport of free'' electrons through solids are highlighted. We also discuss recent observations of convoy electron emission in ion-surface collisions at small glancing angles. 36 refs., 13 figs.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Convoy Electron Emission Produced in Ion atom Ion foil and Grazing Angle Ion surface Collisions written by Jong Yeon Lim and published by . This book was released on 1996 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 ERDA Energy Research Abstracts written by and published by . This book was released on 1983 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Exit Charge State Dependence of Convoy Electron Production in Heavy ion Solid Collisions written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The dependence of the yield of convoy electrons emitted near the forward direction in collisions involving fast ions and thin solid targets on the emergent projectile charge state is presented and described in terms of primary electron loss events in the solid. The data include a large array of projectiles, projectile energies and charge states, as well as targets ranging in thickness from the non-equilibrium well into the equilibrium thickness region. The description presented is consistent with other experimental and theoretical results indicating that the convoy electron production is closely linked to the ELC process observed in binary ion-atom collisions, with the dominant contribution to the convoy yield stemming from excited states of the projectiles. 22 refs., 3 figs.
Download or read book Shim 89 Proceedings Of The First International Symposium On Swift Heavy Ions In Matter written by J. Remillieux and published by CRC Press. This book was released on 1989 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Treatise on Heavy Ion Science written by D.A. Bromley and published by Springer Science & Business Media. This book was released on 2012-11-27 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: For 75 years the stopping of energetic ions in matter has been a subject of great theoretical and experimental interest. The theoretical treatment of the stopping of ions in matter is largely due to the work of Bohr, 1-3 Bethe,4-6 Bloch,7. s and Lindhard,9-12 and it has been reviewed by Bohr,3 Fano,13 17 20 Jackson,14 Sigmund,15 Ahlen,16 and Ziegler et al. - Soon after the discovery of energetic particle emission from radioactive materials, there was interest in how these corpuscles were slowed down in traversing matter. In 1900, Marie Curie stated 21 the hypothesis that Hies rayons alpha sont des projectiles materiels susceptibles de perdre de leur vitesse en travers ant la matiere." Early attempts to evaluate this were incon clusive for there was not yet an accurate proposed model of the atom. Enough experimental evidence was collected in the next decade to make stopping power theory one of the central concerns of those attempting to develop an atomic model. J.J. Thomson, director of the prestigious Cavendish Laboratory, and Niels Bohr, a fresh postdoctoral scientist at Rutherford's Manchester Laboratory, both published almost simultaneously22. 23 an analysis of the stopping of charged particles by matter, and each contained many of their divergent ideas on the model of an atom. Thomson ignored in his paper the Rutherford alpha-particle scattering 24 experiment of a year before. But the nuclear atom with a heavy positively 25 charged core was the basis of Bohr's ideas.
Download or read book Electronic and Atomic Collisions written by Donald C. Lorents and published by North Holland. This book was released on 1986 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interaction of Charged Particles with Solids and Surfaces written by Alberto Gras-Martí and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 699 pages. Available in PDF, EPUB and Kindle. Book excerpt: Early in 1989, while most of us were gathered in the Mediterranean five-centuries-old city of Alacant, the idea of a school on stopping and particle penetration phenomena came to our minds. Later that year when discussing this plan with some of the participants in the 13th International Conference on Atomic Collisions in Solids in Aarhus, we were pleased to note that the proposal was warmly welcomed indeed by the community. An Advanced Study Institute on this or a related subject had not been organized in the last decade. Because of the progress made particularly in the interaction of high energy beams with matter, and the many applications which the general subject of the stopping of charged particles (ions and electrons) in matter enjoys, a Study Institute appeared a worthy enterprise. Even though several international conference series cover developments in these areas, they miss tutorial introductions to the field. The title chosen was Interaction of Charged Particles with Solids and Surfaces, and the objectives were stated as follows: "to cover theory and experiments, including selected applications and hot topics, of the stopping of charged particles (ions and electrons) in matter. The emphasis will be on outlining the areas where further effort is needed, and on specifying the basic needs in applications. Fundamental concepts will prevail over applications, and the character of the Institute as a school will be stressed. " The school was directed by Fernando Flores (Spain), Herbert M. Urbassek (Germany), Nestor R.
Download or read book State of the art Reviews On Energetic Ion atom And Ion molecule Collisions written by Dzevad Belkic and published by World Scientific. This book was released on 2019-10-17 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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'.
Download or read book Physics Briefs written by and published by . This book was released on 1991 with total page 826 pages. Available in PDF, EPUB and Kindle. Book excerpt:
