Electron-impact double-ionization processes of light positive ions from He- to Ne-like isoelectronic sequences, as well as of the heavy ions Arq+ (q = 1–7) and Kr q+ (q = 1–4) are considered for incident-electron energies E < 50 Ith where Ith is the threshold energy for double-electron ionization. On the basis of reliable experimental data and quantum-mechanical calculations, simple semiempirical formulae with three fitting parameters, by taking into account the contribution of direct double ionization and of inner-shell ionization processes, are obtained which describe the experimental cross sections within an accuracy of 20–30%. With this accuracy, the formulae suggested can be used for prediction of the double-ionization cross sections of positive ions with the nuclear charge Z ⩽ 26 in the electron energy range of E < 50Ith. According to the model suggested, the direct ionization cross section σdir (simultaneous ionization of two outer electrons) is scaled as I−3th against scaled electron energy E/Ith and contains only one fitting parameter. Two additional fitting parameters are obtained using the least-squares method in conjunction with numerically calculated single-electron inner-shell ionization cross sections. All fitting parameters are found to be constant for ions within a given isoelectronic sequence. The present analysis also provides a method for indirect determination of K-shell ionization cross sections for ions from Be-like to Ne-like sequences. The fluorescence yields ωK for a single K-shell vacancy in ions from Li-like to Ne-like sequences with nuclear charges 3 ⩽ Z ⩽ 26 are calculated as well.

New experimental data on double-ionization cross sections of neutral atoms, positive and negative ions by electron impact are reported. These and other relevant data are compared with recent multiple-ionization semiempirical formulae extended for the case of two-electron ionization. Theory gives analytical dependence of the double-ionization cross sections on the main parameters of the collision system in a wide energy range. For the He atom, He-like ions and H − ion high-energy asymptotic behaviour of the double-ionization cross sections are considered on the basis of a quantum mechanical treatment. Suggested cross section scaling for fast collisions, employing a target-effective nuclear charge, is in good agreement with experimental data.

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During the last ten to fifteen years an almost explosive progress could be obtained in the Physics of Highly Charged Ions. To summarize this progress in all important results is the principal aim of Volume 13 of SPRINGERS Series in Electrophysics. The qualification of the authors for this work is beyond any question. They have been active in the field under consideration for a long time and have contributed to the progress mentioned.Of course the limited volume of the book requires a rigorous selection and weightening of the facts.Particular attention is paid to the presentation of theoretical methods. Here the reader gets an excellent general view of the recent developments and the present state in the theory of multiply charges ions.Experimental results are mostly used only for the illustration of the theoretical models. The description of the experimental techniques (equipments, measuring methods etc.) is outside the scope of the book.The well devided monograph starts with an (rather short) introduction, containing some historical remarks and the summary of the application aspects of highly charged ions. In several fields of applied physics and technology such ions are of increasing importance. Examples are: High Temperature Plasma Physics (especially controlled Thermonuclear Fusion), Astrophysics (especially Solar Physics), Accelerator-Based' Physics, Material Sciences and Laser Research.The two following chapters deal with the structure and the radiative processes of highly charged ions. The basic properties of the spectra caused by the strong and unshielded Coulomb field of the ions are discussed in great detail. One of the most characteristic features is the presence of so-called satellite lines which are emitted by ions of the preceding ionization stages. The satellite lines play an essential role in modern x-ray spectroscopy. Based on the solution of the corresponding eigenvalue problem the principles of the systematic calculation and classification of the spectra of highly charged ions (including both usual lines and satellites) are given. The correct interpretation of the spectra requires the inclusion of relativistic and radiative effects in the calculations. These effects increase as the ionic charge inreases.The main part of the monograph (chapters 4-9) is devoted to the large variety of collision processes of multi-charged ions.At first a detailed account on the existing theoretical description of excitation processes in electron-ion collisions a t non-relativistic energies is presented. The results of the different methods (R matrix, Generalized Quantum Defect Method, Asymptotic Expansion) are compared with the (rather scarce) experimental results.After that the electron-ion ionization processes are analysed taking into account mainly the direct and exchange channels of single-electron ionization. A comparison between theoretical and experimental results completes this analysis, too.The collisions of heavy particles (atoms, ions, molecules) with highly charged ions are the central problem of the m...