Перегляд за Автор "Kvasikova, A. S."

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  • Ескіз
    Документ
    On some numerical model to solving dynamical equations of nonrelativistic and relativistic backward-wave tube
    (Одеський національний університет імені І. І. Мечникова, 2022) Tkach, T. B.; Kvasikova, A. S.; Shpinareva, Iryna M.; Ткач, Т. Б.; Квасикова, А.С.; Шпінарева, Ірина Михайлівна
    It is developed an effective computational approach to solution the master corresponding system of differential equations, which describe the nonlinear stationary and nonstationary electromagnetic processes in the nonrelativistic and relativistic backward-wave tubes (carcinotrons) with maximal accounting for the different physical factors such as the relativistic effects, effects of dissipation, the presence of a space charge, wave reflections at the ends of the slowing system, stochastic factors by means including the special elements in a whole system etc as well as the detailed investigation of characteristics (dynamical and topological invariants) of dynamics of a carcinotron in automodulation and chaotic regimes with construction the corresponding bi-furcation diagrams. Below in order to further solve the master system of dynamical equations for carcinotron it is presented in brief the realizing numerical scheme, based on the use of the conservative finite-difference schemes of the "predictor-corrector" type and the sweep algorithm.
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    Документ
    Optimized quantum defect method in relativistic theory of spectra of Li-like multicharged ions
    (Одеський національний університет імені І. І. Мечникова, 2022) Kvasikova, A. S.; Shpinareva, Iryna M.; Tkach, T. B.; Квасикова, А. С.; Ткач, Т. Б.; Шпінарева, Ірина Михайлівна
    The relativistic theory of radiative transitions using the general relativistic quantum defect approximation (GDA) was also used to study the wavelengths and oscillator strengths for the 1s22s (2S1/2) → 1s23p (2P1/2) transitions in Li-like multicharged ions with a nuclear charge Z= 14-70. and. The obtained results were compared with available theoretical and experimental (summarized) data. An important point is related to the accurate accounting of the complex contributions of the exchange-correlation (polarization) effect and the use of an efficient singlequasi- particle representation based on the general relativistic approximation of the quantum defect, which significantly ensures a physically reasonable agreement between the theory and the experiment.
  • Ескіз
    Документ
    PHOTOELECTRON SPECTROSCOPY OF DIATOMIC MOLECULES: OPTIMIZED GREEN’S FUNCTIONS AND DENSITY FUNCTIONAL APPROACH
    (Одеський національний університет імені І. І. Мечникова, 2018) Ignatenko, A. V.; Glushkov, A. V.; Lepikh, Yaroslav I.; Kvasikova, A. S.; Игнатенко, А. В.; Глушков, А. В.; Лепих, Ярослав Ильич; Квасикова, А. С.; Ігнатенко, Г. В.; Глушков, О. В.; Лепіх, Ярослав Ілліч; Квасикова, Г. С.
    We present the optimized version of the hybrid combined density functional theory (DFT) and the Green’s-functions (GF) approach to quantitative treating the diatomic photoelectron spectra. The Fermi-liquid quasiparticle version of the density functional theory is used. The density of states, which describe the vibrational structure in photoelectron spectra, is defined with the use of combined DFT-GF approach and is well approximated by using only the first order coupling constants in the optimized one-quasiparticle approximation. Using the combined DFT-GF approach leads to significant simplification of the calculation and increasing an accuracy of theoretical prediction.
  • Ескіз
    Документ
    Strong field DC stark effect in bulk semiconductors and heterostructures (quasi 1-D quantum wires): advanced theory and new applications
    (Одеський національний університет імені І. І. Мечникова, 2014) Glushkov, Oleksandr V.; Lepikh, Yaroslav I.; Florko, Tetyana A.; Kvasikova, A. S.
    At present, an intensive studying semiconductor quantum wells, quantum wires, and quantum dots is provided by a set of factors, including a great progress in ultrashort-pulse spectroscopy methods together with increasing effectiveness in crystal-growth techniques of various quantum confined systems. Above very complex and actual problems of modem nano-electronics one could note the optical Stark effect, of quantum beats, and of the photon echo in the bulk and quantum well semiconductors.