Study On The Atomic Radiative Transitions And Auger Decays Of Inner Shell Vacancy States Within The R-matrix Method

The radiative transitions of the atoms are of great significance in the research of astrophysics, nuclear fusion, and so on. The investigation of element abundances requires a complete set of accurate atomic data, including energy levels and transitions probabilities, and in the field of X-ray astronomy, a large number of parameters for the atomic inner shell radiative and Auger transitions are necessary to analyse the high resolution spectra. Inner shell processes are also an interesting topic in the investigation of the interaction of X-rays and atoms. In this thesis, the atomic structures, the radiative transitions of both outer and inner shells, and Auger decays of inner-shell hole states are studied within the R-matrix method.Firstly, the energy levels, oscillator strengths, and photoionization cross sections of Cu I and Zn I are calculated to provide atomic data for the study of element abundances in astrophysics. The calculations are carried out in the LS-coupling scheme, and extensive configuration interactions are included to properly delineate the quantum states involved. Comparisons are made with available experimental and other theoretical results, and the agreement is generally good. Due to the excitations of the 3d subshell, the atomic structures of the two atoms are complicated. The photoionization cross sections of Cu I display many resonances belonging to 3d hole states, and they are expected to play an important role in modelling the particle distribution in hot plasmas.Secondly, the spontaneous emissions and Auger transitions of single K-hole and hollow states of Ne isonuclear sequences are systematically studied. The total decay probabilities of single and double K-hole states are dominated by the main Auger transitions, namely K-LL and KK-KLL Auger decays, respectively. The target states corresponding to these main Auger trasitions have been carefully choosen to insure they were included in the calculations, and the contributions of some shake channels were evaluated. The characteristics of the K-shell hole states, such as resonance energies, spontaneous emission probabilities and Auger widths, are obtained from the photoionization cross sections of certain initial states in the 1s-2p resonance regions. Good agreement is found between our calculations and the experimental X-ray spectrum and Auger electron spectrum. For the radiative transition probabilities and the Auger widths, there are considerable discrepacies among different theoretical investigations, even for the calculations using the same method, and the present calculation should be more convergent.Lastly, the photoionization cross sections of the ground state of Ne I and the single K-hole state of Ne II in the regions of the K-edge are calculated. The former has already been studied both experimentally and theoretically, and the present result agrees well with the data measured recently. However, the later is presented for the first time, which is corresponding to the second step for the production of the hollow state by sequentially K-shell photoionization with an intense X-ray. For the Rydberg series of the 1s-np resonances, the resonant Auger effects are considered by superimposing the independent Lorentz profiles, except that the lowest one 1s-3p resonances are directly calculated since all the main Auger channels are included in these close-coupling calculations. Above the K-shell thresholds, the photoionization cross sections display many weak resonances belonging to the core-valence double excitations.