R Karazija

Auger cascade satellites following 3d ionization in xenon

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 Nobel prize in physics - regularities and tendencies

Various distributions of the Nobel laureates in physics in the 20th century and their discoveries are considered. It is shown that the time-interval between the discovery and its recognition can be approximately described by a lognormal distribution. The ratio of the numbers of laureates awarded for the experimental and the theoretical discoveries was rather different in various decades; this was determined by some “waves” of discoveries and in the initial period probably by some subjective factors. The probability to obtain this prize for the theorist is larger than for the experimenter. The main part of the awards was given to the scientists working in the main fields of modern physics: small distances and solid state physics. Some fields of physics such as mathematical physics, relativity, statistical physics were ignored completely. The worrying tendency of an increasing average age of laureates towards their retirement age is indicated.

On the interpretation of the intense emission of tungsten ions at about 5 nm

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 W29+–W37+ corresponds to the same transitions 4p64dN→ 4p54dN+1+ 4p64dN−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 4p1/2–4d3/2 to the open 4dN3/2 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.

Global characteristics of atomic spectra and their use for the analysis of spectra. IV. Configuration interaction effects

Changes of the moments of atomic spectrum due to configuration interaction (CI), the CI strength, the average shift of the energy of a level due to its interaction with all levels of distant configuration and other global characteritics of CI effects in atoms are systematised and their expressions presented. The results of the calculation of these characteristics for the energy level spectra of the 3s3p3 + 3s23p3d configurations in Si isoelectronic series, 3p53dN + 3p63dN−24p + 3p63dN−24f (N = 5, 6, 7, 8) in Cr, Mn, Fe and Co isoelectronic series, ns2 npN + npN+2 at n = 2 – 5 and N = 2 – 4 in neutral atoms as well as for the characteristic emission spectra corresponding to the 3p53d9 + 3d74p → 3d8 transitions as well as for the Auger M4,5N1N2,3 spectra in Kr and N4,5O1O2,3 in Xe are given and compared with the same characteristics of the more complete experimental spectra.

The essential role of many-electron Auger transitions in the cascades following the photoionization of 3p and 3d shells of Kr

Using the relativistic configuration interaction method it is shown that many-electron Auger transitions—discrete double Auger effect and hypersatellite Auger transitions—play an essential and even dominant role in the de-excitation of 3d−1 and 3p−1 vacancy states in Kr. Also various other many-electron Auger transitions (transitions with a shift of vacancy into a deeper shell as well as triple Auger transitions and hypersatellite Auger transitions with additional excitation of electrons) manifest themselves during the cascades due to the correlation effects and appearance of configurations with several vacancies. Good correspondence with the branching ratios of ions measured by the coincidence technique is obtained, and thus the existing discrepancy with the previous calculation results is removed.

Global characteristics of atomic spectra and their use for the analysis of spectra. III. Auger spectra

Expressions for the average energy, variance and skewness of Auger spectra are presented. These characteristics have been calculated for the M4, 5 N4, 5 N4, 5 spectra of free atoms with open 5pN shell and for the N4, 5 N6, 7 N6, 7 spectra of lanthanide atoms; a comparison with the global characteristics of the registered spectra is given. The transition zones of the Auger spectrum are introduced. These zones characterise the participation of the initial and final configurations in Auger transitions. It is shown, that the effect of narrowing takes place in Auger spectra as it does in characteristic emission spectra.

CASCADES AFTER K-VACANCY PRODUCTION AND ADDITIONAL IONIZATION OR EXCITATION IN ATOMS OF LIGHT ELEMENTS

The results of Auger and radiative cascades after the production of a vacancy in the K-shell and the additional ionization or excitation of the other shell are presented for the various ions of astrophysically important elements, namely, Ne, Mg, Si, S, and Ar. The detailed level-by-level calculations are performed using a single-configuration quasi-relativistic approximation. The populations of the levels of the excited configurations produced during a cascade as well as for the final ions are presented. These data enable us to take into account two-electron processes at the K-shell ionization, and thus to supplement the results of our earlier investigation of K-vacancy cascades.

Auger decay of 3p-ionized krypton

A theoretical study of Auger cascades during the decay of 3p{sub 1/2} and 3p{sub 3/2} vacancies in krypton has been performed by level-by-level calculations using a wide configuration interaction basis. Auger spectra for all steps of the cascades are presented and are compared with the existing experimental data. Good agreement of our results with the branching ratios of ions measured by a coincidence technique is obtained.

Global characteristics of atomic spectra and their use for the analysis of spectra. II. characteristic emission spectra

The derivation of explicit expressions for main global characteristics of the characteristic emission spectrum and the emissive and receptive zones of the configurations involved in transitions is described. All types of transitions for which emissive or receptive zone coincides with the corresponding configuration are found. The mean deviation from the average energy and skewness are investigated by comparing the theoretical values with the results obtained from the existing experimental data for the transitions 3dN 4p → 3dN + 1 in the three times ionized atoms, 4d9 4fN → 4d10 4fN - 1 in the neutral lanthanides and 3d84p + 3p53d10 → 3d9 in the Co I isoelectronic sequence. The global characteristics of spectra are employed to investigate the shift and the narrowing of the emission spectrum, as well as to calculate the multiplet broadening of Kα1,2 lines in the iron group elements and the satellite shifts of these lines that are due to the additional ionization of atoms.

Cascades after k-vacancy Production in Atoms and Ions of Light Elements

The results of detailed level-by-level calculations of Auger and radiative cascades after K-vacancy production are presented for the astrophysically important elements, namely Ne, Mg, Si, S, and Ar. Calculations are performed using the single-configuration, quasi-relativistic approximation. The whole isonuclear sequence of ions for a given element is considered. For the first time, the dependence of the cascade on the initial vacancy state is investigated. The populations are presented not only for the levels of the final configurations, but also for the levels of the excited configurations after the Auger transitions. An intense characteristic emission can be observed from such levels.