Thesis is devoted to the development of the method of interacting configurations in the complex numbers representation. The investigation of the energetic positions and widths of autoionizing states, which are formed in the process of ionization of Be, Mg and Ca atoms by electron-impact and as a result of photoionization, is under consideration. The purpose of the research is achieved in step by step complication of calculations of the energetic positions and widths of autoionizing states, which are formed in the process of ionization of atomic systems, from the ions to the multielectron atoms.
Fundamental aspect of actuality consists in the extension of the method application for multielectron atomic systems. The method of interacting configurations in the complex numbers representation gives the possibility to calculate both the energetic positions and widths of autoionizing states. Moreover, not only the scattering process but the process of atomic systems ionization by electrons and photons as well can be investigated in this method. We investigate the process of atomic systems ionization by electrons and photons, which, contrary to the scattering process investigation, is some problem of modern theory.
The applied aspect of actuality is ensured by the role of autoionizing states as a source of information on the structure of spectra of atoms and ions, on the effective cross sections of processes and transition probabilities. Indeed, the autoionizing states play the important role in all processes of electron-atomic and electron-ionic collisions due to the fact that usually the resonance ionization cross sections can dominate several times over the direct ionization cross sections. The reason is in quasistationary states existence. This is an important aspect of the low-temperature plasma diagnostics. Moreover, the excitation and decay of autoionizing states is a clear manifestation of correlation effects in the electron shells of atoms. Therefore, these processes are among the main problems in modern physics of electron-atomic collisions.
The main scientic results for defence are as follows.
The calculating possibilities of the method of interacting configurations in the complex numbers representation have been developed successfully. The method has been applied for the first time to the calculations of the total and partial characteristics of the Be, Mg, Ca atoms autoionizing states. Hence, the possibilities of the method application have been extended for the description of the multielectron atomic systems.
The choice of the atom ground state wave function for adequate description of the multielectron atoms ionization processes has been justified. The comparison and analysis of the quasistationary states characteristics calculated on the basis of different multipapametric wave functions of the atom ground state have been performed. Due to the adequate choice of the ground state wave function, the accuracy of calculations is essentially improved.
The effect of essential changes of partial widths in comparison with the total widths, when the different ground state wave functions were applied, has been observed for the first time.
The energetic positions and widths of the ions H-, Li+, Be++ and atoms Be, Mg, Ca autoionizing states are calculated in the framework of the exact quantum-mechanical method of interacting configurations in complex numbers representation. The method is well known due to the precise description of the helium atom quasistationary states.
The method of interacting configurations in complex numbers representation has been applied successfully for more complicated problem as the scattering of electrons by ion. The process of multielectron atoms ionization has been calculated.
The energies and widths of the lowest autoionizing states of the Be, Mg, Ca atoms have been clarified.
The advantages of the method of interacting configurations in complex numbers representation, in comparison with other methods of calculations of multielectron atomic systems, have been demonstrated. It is shown that advantages are in automatic receiving both the energies and widths of the quasistationary states, as well as in the possibility to describe the ionization processes of multielectron systems.
