Relativistic Theoretical Study On The Radiative And Non-radiative Processes Of Complex Atoms

The aims of the atomic physics are focus onto the atomic structure and the regularity of the interaction with other microcosmic particles. The theoretical calculation on atomic structure can be used to understand the atomic structure and analyze the experimental spectra.The relativistic multi-configuration Dirac-Fock (MCDF) method is one of the best widespread used methods in the calculation of atomic structures and properties. In this method, an atomic state wave function (ASF) is constructed by a linear combination of a series configuration state wave function (CSF) in N-electron Hilbert space. By using the variational principle to determine the energy expectation value of the relativistic Dirac-Coulomb Hamiltonian, all of the radial functions, configuration mixing coefficients, and the total binding energies can be determined automatically. In order to make a more accurate calculation, we must take higher order effects into account, such as Breit interaction, QED correction, and finite nuclear effects. This method had made a good progress on the calculation for the energy levels and wave functions of complex system which include more than one open shell.Using the Multi-configuration Dirac-Fock method (MCDF), we studied the characteristic of the decay processes of the 4d core excited states of CsIV, the low-lying excitation structure of super-heavy element Bohrium (Z=107) and the X-ray spectra of the 3d-4f transitions of highly charged Xenon ions in details in this work, by including the electron correlation and the relaxation effects systematically.The core excited states can decay to a lower state via two decay channels. The one is radiative decay channel, the other is non-radiative decay channel,i.e. Auger process. In Chapter three, we introduced the decay process of the core excited states, of CsIV. The energy level structures of the 4d core excited configuration 4d 5s25p5, final radiative configuration 4d105s25p4 and final Auger configurations 4d105s25p3 and 4d105s15p4 of CsV ion and all possible decay dynamics processes related to these configurations are all determined by MCDF method. We also compared the present results of radiative transition, oscillator strength and the line width with the results obtained by experimental spectra and the quasi-relativistic configuration interaction method and got a good agreement. We also make prediction for some dominant features of the Auger electron spectrum emitted by the Auger decay process of the 4d95s25p6 core excited states.The importance of the study of the super-heavy element is shown in experimental and the theoretical. Generation of new nuclear elements is an important symbol of the research ability of a country. Theoretical study on such element, not only can help the rule for the considering of the relativistic and correlation effect in the many electron system, but also can give an identification for the validity of the.present theory in the limited case. In the Chapter four, we studied some low-lying absorption spectroscopy and the resonant absorption probability of bohrium (Z = 107) by using MCDF method which included the correlation effects and relativistic effects systematically. We got some satisfied results ofthe ionization energy which make a good agreement with the results obtained by the semi-empirical method.The theory of atomic structure also play an important role in the analyzing of the experimental spectra. So we investigated the X-ray spectra of 3 d-4f transitions of multiply charged Xenon ions in Chapter five. Experimental quasi-continuum spectra in the range of 12.5-15.5A generated from the plasmas which produced by the intense picosecond irradiation of a gas of xenon clusters are reproduced well by the present theoretical work. We also point out that the effect of the presence of spectator electrons for the diagram lines is the main contribution of the formation of quasi-continuum spectra.