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The electron spectra of xenon have been measured at the kinetic energy region of 8–40 eV using synchrotron radiation excitation below and above the 3d ionization threshold. The hole in the 3d orbital leads to the cascade of Auger transitions, the final steps of which give rise to pronounced satellite structures at the low kinetic energy region. In order to estimate the satellite production, the average kinetic energies and transition probabilities of Auger transitions after 3d ionization have been calculated using the method of global characteristics. Furthermore, the fine structure of the most intense satellite Auger transitions has been calculated using the pseudorelativistic Hartree–Fock method, and the results have been used to assign the main satellite peaks. In addition, the production of multi-charged Xe ions has been investigated and the role of electron–electron interaction in explaining the remaining differences between experiment and theory has also been discussed.

The origin of the intense emission band at about 5 nm, dominating the emission spectra of tungsten ions in the ASDEX Upgrade tokamak and EBIT, is discussed. It is shown that the emission spectra of various ions calculated taking into account only the excitations from the ground level agree fairly well with the results obtained in the collisional-radiative model; thus, the contribution of the excitations from the other levels is small. Though the excitation spectrum for all sequence of ions W 29+ -W 37+ corresponds to the same transitions 4p 6 4d N → 4p 5 4d N+1 + 4p 6 4d N−1 4f, its energetic width essentially changes going on from the charge of ion q = 34 to q = 35. It is caused by the appearance of the excitations 4p 1/2 -4d 3/2 to the open 4d N 3/2 subshell, which are not quenched by configuration mixing. The satellite line at about 4.5 nm is explained by the transitions of the same type, although between configurations with one spectator 5s electron. The existence of one more group of intense lines in the region of 2 nm, corresponding to 5s-4p transitions, is predicted.

Magnetic dipole transitions between the levels of ground 4d N configurations of tungsten ions were analyzed by employing a large basis of interacting configurations. Previously introduced configuration interaction strength between two configurations was used to determine the configurations with the largest contribution to wave functions of atomic states for the considered configurations. Collisional-radiative modeling was performed for the levels of the ground configuration coupled through electric dipole transitions with 4p 5 4d N+1 and 4d N−1 4f configurations. New identification of some lines observed in the electron-beam ion trap plasma was proposed based on calculations in which wavelength convergence was reached.

The contribution to electron-impact ionization cross sections from excitations to high-nl shells and a consequent autoionization is investigated. We perform relativistic subconfiguration-average and detailed level-to-level calculations for this process. Ionization cross sections for the W27+ ion are presented to illustrate the large influence of the high shells (n ^ 9) and orbitals (/ > 4) in the excitation-autoionization process. The obtained results show that the excitations to the high shells (n ^ 9) increase cross sections of the indirect ionization process by a factor of 2 compared to the excitations to the lower shells (n < 8). The excitations to the shells with orbital quantum number l = 4 give the largest contribution compared with the other orbital quantum numbers /. Radiative damping reduces the cross sections of the indirect process approximately twofold in the case of the level-to-level calculations. Determined data show that the excitation-autoionization process contributes approximately 40 % to the total ionization cross sections.

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The Coulomb exchange interaction operator and its matrix elements are represented in a special form, which enables the investigation of groups of terms, caused by this interaction, and the construction of new wavefunction bases. ?he existence of distinct upper and lower groups ofterms due to exchange interaction in configurations "(1-I)-'nlN and n14'i2-Nn(l+ I ) for small numbers of electrons or vacancies N = 1.2 is shown. The separation of groups becomes more pronounced in the two-configuration approximation on taking into account correlations with symmetric exchange of symmetry. In this case a new wavefunction basis is proposed.

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