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It is shown that the calculation of atomic constants by some versions of the multi-configurational method, or its relativistic generalizations, violates the principles of a consistent theory based upon the quantum electrodynamic (QED) approach. The consequences of this violation for the radiative transition probabilities are under investigation. We obtained the probabilities of innershell radiative transitions in Ne-like argon and iron in the lowest approximation of a consistent theory. These results are compared with the corresponding data from some recent publications.

The problem of the construction of the optimal one-electron representation in the theory of the multielectron atom is reduced to the minimization of the gauge dependent multielectron contribution to the radiation widths of atomic levels. The minimization criterion is numerically tested by calculation of the resonance radiation transition probability in the Na-like ion SVI taking into account the core polarization effects.

Evolution of levels populations in Ar plasma with varying parameters is under theoretical investigation. The model imitates fast compression and expansion of the capillary plasma column. The role of the HYDROGEN admixture is discussed.

An energy approach based on consistent QED theory is outlined which presents the energy of any decaying atomic state in complex form with the imaginary part responsible for different types of decays. The aim is to study, in a uniform manner, elementary processes responsible for emission-line formation in plasmas. The energy approach is generalized here for the collisional problem. Numerical results on electron collisional strengths and rate coefficients for Ne-like ions are presented. It is shown that collisional rate coefficients are close to their maxima at an electron temperature∼0.30E threshold for iron and ∼0.15E threshold for argon

For pt.I see ibid., vol.10, p.1001 (1977). A formally exact perturbation expansion with a model zeroth-order approximation has been applied to the semi-relativistic equation for a many-electron system. The energy levels of Mo and Zr ions with two electrons or two vacancies above the 1s22s22p63s23p63d10 core have been calculated. It is shown that the experimental spectra for systems with two quasi-particles above the core may be used to investigate more complex spectra, with three or more quasi-particles.

Asymptotically precise calculations have been carried out with n to infinity , for the Rydberg states 4f136sns of the Tm atom, the 4f146sns, 4f146snp states of the Yb atom and the Lu+ ion, the 4f14ns, 4f14np, 4f14nd states of the Yb+ and Lu2+ ions and the 4f146s2ns, 4f146s2np, 4f146s2nd states of the Lu atom. The Lu atom and Yb+ and Lu2+ ions are considered as a system with one electron above the core of the closed shells 4f146s2 or 4f14. The Yb atom and Lu+ ion are regarded as a system with two electrons above the core. The Tm atom is considered as a system with 4f-1 vacancy and the 6s, ns electrons above the 4f14 core. In calculating energies with one electron above the core the energy is extrapolated as a function of the principal quantum number n by the model potential technique. The potential constructed at this stage is used as a zero-order approximation in calculating states with two and three quasiparticles (vacancies and electrons) above the core. The corrections for the energies of the states of two- and three-quasiparticle systems are calculated with the use of the perturbation theory. The first order has been allowed for completely. In the higher orders effective allowances have been made for the corrections which with n to infinity make contributions of approximately 1/n3. Consideration is given to the non-Coulomb features of Rydberg spectra not vanishing within n to infinity .

A model potential relativistic method is used to calculate the energies of the lower levels with configurations 4s4p, 4p2, 4s4d, 4p4d in the Zn I isoelectronic series for nuclear charges Z=36-50. The calculation is made in the first order of perturbation theory with the effective inclusion of higher corrections. The role of various correlation effects is evaluated: core polarisation due to outer electrons, superposition of configurations, mutual screening of the outer electrons. As a zeroth approximation the authors obtain the wavefunctions of the outer electron in the field of the core model potential; the model potential parameter being determined from the empirical energy levels of Cu-like ions. An extrapolation procedure for model potential parameters is used for the calculation of energy levels of Cu-like ions. Energy levels 4lj and 5lj of Cu-like ions for Z=36-60 are given with an accuracy of about 0.1%. The accuracy of the energies of Zn-like ions is within 1%.

The first few terms of the perturbation expansions for the function and the energy shift of a degenerate state of an arbitrary quantum mechanical system are obtained using the adiabatic formula. It is shown how the expansion for the secular operator may be obtained from the expansion for the function. The results are used to calculate energies of the ground and some excited states and multiplet splittings of some beryllium-like ions.

The relativistic perturbation theory is applied to the solution of the many-electron Dirac equation. The theoretical consideration is accomplished for some Mg-like ions: S V, Ca IX, Ti XI and Fe XV; the energies of all the states 1s2 2s2 2p6 3l1j1, 3l2j2 are calculated. The Ne-like spectra are calculated for the ions with Z = 16-26; all the states of configurations 1s2 2s2 2p5 3s, 3p, 3d and 1s2 2s2p6 3s, 3p, 3d are considered. The Dirac equation with the central one-particle model potential Vc(r) is accepted as a zeroth approximation; the model potential imitates the core potential of the closed shells. The empirical information about the energy structures of one electron above the core or one vacancy inside the core is used here to construct the zeroth approximation. The perturbation theory first order correction is calculated exactly, the high order contributions are accounted for effectively. Two main types of high order corrections are investigated: "polarization" interaction of two "above core" particles and effect of the mutual screening of these particles.

The Kalpha and Kbeta radiation from Fe, Ni and Ti plasmas in a low inductive spark has been investigated both experimentally and theoretically. A high-dispersion and high-resolution Johann crystal spectrograph has been used for the measurements. The theoretical analysis is based on relativistic perturbation theory with a zero-order model approximation. Some Kalpha and Kbeta spectra features are qualitatively explained and some Kbeta lines are identified for the first time. It has been shown that the observed time and space integrated spectrum is due mainly to the low M-shell ions. The calculation shows that this qualitatively explains the long-wavelength Kalpha plasma radiation shift relative to the solid state Kalpha line. The Kalpha radiation from high ions would be shifted to the opposite side.

Wavelengths of 4-5 and 4-4 transitions have been measured experimentally for the Cu-like ions Ag XIX-Sn XXII (Z = 47-50). The Relativistic Model Potential Method has been used for extrapolation and interpolation of the 4lj and 5lj energy levels in the range Z = 36-80. Two versions of calculations were made. In the first one the experimenal energies for Z = 36, 42, 56, 62 were used as references; these results are in good agreement with the new experimental data are used to obtain more accurate calculated values for large Z.

An investigation is made of the energy transfer between the Gd3+ and Mn2+ ions in CaF2Gd, Mn crystals under photoexcitation. The studies performed at varied concentrations and with measurement of the lifetimes of the excited states reveal that the process is intracentric and that only the noncubic luminescent centres of gadolinium seem to be involved in the energy transfer from the Gd3+ ions to the Mn2+ ions. [Russian Text Ignored].

A semiempirical method is proposed for taking into account the spin-orbit interaction in calculating line intensities for transitions in atoms and molecules. Use of the method is demonstrated for SX and CaXIV ions.