Electron Impact Ionization
Electron Impact Ionization

Author: T.D. Märk

Publisher: Springer Science & Business Media

Published: 2013-06-29

Total Pages: 395

ISBN-13: 3709140285

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It is perhaps surprising that a process which was one of the first to be studied on an atomic scale, and a process which first received attention over seven decades ago, continues to be the object of diverse and intense research efforts. Such is the case with the (seemingly) conceptually simple and familiar mechanism of electron impact ionization of atoms, molecules, and ions. Not only has the multi-body nature of the collision given ground to theoretical effort only grudgingly, but also the variety and subtlety of processes contributing to ionization have helped insure that progress has come only with commensurate work: no pain - no gain. Modern experimental methods have made it possible to effectively measure and explore threshold laws, differential cross sections, partial cross sections, inner-shell ionization, and the ionization of unstable species such as radicals and ions. In most instances the availability of experimental data has provided impetus and guidance for further theoretical progress.

Analysis of Excitation and Ionization of Atoms and Molecules by Electron Impact
Analysis of Excitation and Ionization of Atoms and Molecules by Electron Impact

Author: Afzal Chaudhry

Publisher: Springer Science & Business Media

Published: 2010-10-17

Total Pages: 236

ISBN-13: 1441969470

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The content of this book describes in detail the results of the present measurements of the partial and total doubly differential cross sections for the multiple-ionization of rare gas atoms by electron impact. These measurements show, beside other trends, the role of Auger transitions in the production of multiply ionized atoms in the region where the incident electron energy is sufficient to produce inner shell ionization. Other processes like Coster-Kronig transitions and shake off also contribute towards increasing the charge of the ions. The incident electron having energy of 6 keV, for example, in a collision with xenon atom can remove up to nine electrons! (*) X-ray-ion coincidence spectroscopy of the electron xenon atom collisions is also described. The present measurements of doubly differential cross sections for the dissociative and non-dissociative ionization of hydrogen, sulfur dioxide and sulfur hexa fluoride molecular gases by electron impact are also described in the text of this book. The results of the measurements for sulfur dioxide molecule show how this major atmospheric pollutant can be removed from the atmosphere by electron impact dissociation of this molecule. The present results of the measurements for sulfur hexa fluoride give an insight into the dissociation properties of this molecular gas, which is being so widely used as a gaseous insulator in the electrical circuits. The book also describes the present measurements of the polarization parameters of the fluorescence radiation emitted by the electron-impact-excited atoms of sodium and potassium. In these investigations the target atoms are polarized, therefore, the measurements of the polarization parameters give information about the electron atom interaction in terms of the interference, direct and exchange interaction channels.

Atomic Processes in Electron-Ion and Ion-Ion Collisions
Atomic Processes in Electron-Ion and Ion-Ion Collisions

Author: F. Brouillard

Publisher: Springer Science & Business Media

Published: 2013-03-09

Total Pages: 495

ISBN-13: 146845224X

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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.

Excitation and Ionization of Highly Charged Ions by Electron Impact
Excitation and Ionization of Highly Charged Ions by Electron Impact

Author:

Publisher:

Published: 1989

Total Pages: 15

ISBN-13:

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Two approaches for very rapid calculation of atomic data for high temperature plasma modeling have been developed. The first uses hydrogenic basis states and has been developed and applied in many papers discussed in previous progress reports. Hence, it is only briefly discussed here. The second is a very rapid, yet accurate, fully relativistic approach that has been developed over the past two or three years. It is described in more detail. Recently it has been applied to large scale production of atomic data. Specifically, it has been used to calculate relativistic distorted wave collision strengths and oscillator strengths for the following: all transitions from the ground level to the n=3 and 4 excited levels in the 71 Neon-like ions with nuclear charge number Z in the range 22 (less-than or equal to) Z (less-than or equal to) 92; all transitions among the 2s{sub {1/2}}, 2p{sub {1/2}} and 2p32 levels and from them to all nlj levels with n=3,4 and 5 in the 85 Li-like ions with 8 (less-than or equal to) Z (less-than or equal to) 92; all transitions among the 3s{sub {1/2}}, 3p32, 3d32 and 3d52 levels and from them to all nlj levels with n=4 and 5 in the 71 Na-like ions with 22 (less-than or equal to) Z (less-than or equal to) 92; and all transitions among 4s{sub {1/2}}, 4p{sub {1/2}}, 4p32, 4d32, 4d52, 4f52 and 4f--2 levels and from them to all nlj levels with n=5 in the 33 Cu-like ions with 60 (less-than or equal to) Z (less-than or equal to) 92. Also the program has been extended to give cross-sections for excitation to specific magnetic sublevels of the target ion by an electron beam and very recently it has been extended to give relativistic distorted wave cross sections for ionization of highly charged ions by electron impact.

Excitation and Ionization of Highly Charged Ions by Electron Impact. Progress Report, April 1, 1976--December 15, 1976
Excitation and Ionization of Highly Charged Ions by Electron Impact. Progress Report, April 1, 1976--December 15, 1976

Author:

Publisher:

Published: 1976

Total Pages:

ISBN-13:

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Results have been obtained for the scaled cross sections for ionization from the 1s, 2s and 2p sublevels of hydrogenic ions with Z = infinity. A procedure has been given for obtaining approximate results for ionization of highly charged ions up through neon-like ions from these results. Additional results for excitation of hydrogenic ions with Z = infinity are being obtained. These can be used to obtain additional approximate results for complex ions. Criteria have been obtained for the validity of the assumption that the sublevels of hydrogenic ions are populated in proportion to their statistical weights. The results for many transitions in ions with three valence electrons have been expressed in a simple way in terms of the scaled hydrogenic ion collision strengths Z/sup 2/.cap omega./sub H/ and Z/sup 2/.cap omega./sup e//sub H/. Configuration mixed results for excitation of highly charged Be-like ions have been calculated for 66 transitions. Configuration mixed and parentage mixed results for inner-shell excitation of highly charged Li-like ions have been calculated for 96 transitions. The procedures and programs for calculating excitation cross sections for He-like ions with relativistic corrections are mostly completed and results for a large number of transitions are expected by the end of the contract year.