Relativistic Distorted Wave Study On The Electron-Atom (Ion) Impact Excitations

Electron impact excitation (EIE) process plays a very important role in the modeling and diagnostics of astrophysical and laboratory plasmas, as well as in the development of X-ray laser schemes. At present, we have developed a new rapid and accurate fully relativistic distorted-wave (RDW) program REIE06 to calculate EIE cross sections based on the more efficient and well-known Multi-configuration Dirac-Fork (MCDF) packages GRASP92 and RATIP. The method provided a good chance for us to study EIE process of the complex atoms. In this methods, by using the MCDF wave functions to describe the target-ion states, and the relativistic continuum wavefunctions to describe scattering electron states, the contributions of relativistic and correlation effects on collision strengths and rate coefficients are included automatically in the calculations. In this thesis, firstly, an introduction has been given in Chapter 1, which involves the basic conception, background and the centre goal of this work; Chapter 2 described the MCDF method and RDW method.Secondly, in Chapter 3, a systematical calculations on the differential and integral cross sections for the excitation of the states 2 ³P,3 ³S,3 ³P and 3 ³D of helium from the metastable state 2 3S and which agree with experimental results; The effects of the Breit interaction on the EIE cross sections of He-like isoelectronic sequences ions in different energy of incident electron is studied, and some important conclusions are summarized, which can be expanded to other high charged; Also, the excitation followed by cascade (IEC) is studied. In Chapter 4, we study the EIE process of Li atom. The electron energy loss spectra (EELS) for the inner shell electron excitations of atomic lithium have been simulated. We find that the excellent agreement for the EELS is obtained between the present and experiment in the incident electron energy of 2500eV. But the theoretical EELS of 55～57eV energy region appear the two peaks structures when the incident electron energy below 100eV, which comparing with the experiment of Jiang W C [Chin. Phys. Lett 25 (2008) 3694] have some large discrepancies. We expect that this find is verified in the future experiment. In Chapter 5, we study the EIE process for N+. It is found that the correlation effects are very important for the rate coefficients of N+, when much more correlations are considered, the results agree with experimental results. In Chapter 6, The EIE cross sections from the ground state to all of the 2s²2p⁵3 and 2s2p⁶3 ( =s, p, d) states along the Ne-like isoelectronic sequence ions from Z=50⁵7 have been calculated by using the MCDF package GRASP92 and the RDWB program REIE06. In the calculations, the relativistic effects and electron correlation effects are considered systematically. Based on those calculations, the EIE cross sections along the Ne-like isoelectronic sequence ions in different incident electron energy are discussed, and some important conclusions are summarized. We also study the influence of the correlation effects on the values of the 3C/3D line-intensity ratio [3C: 2p⁵3d ¹P1 -2s²2p^{6 1}S₀, 3D: 2p⁵3d ³D₁ -2s²2p^{6 1}S₀] and the EIE cross sections connected with the 3p→3s (J=2→1, J=0→1) X-ray laser transitions along the Ne-like sequence. In Chapter 7, we reported a complete calculation of the excitation energies and collision strengths from the ground state to excite the occupied 3s, 3p, 3d, and 4s electrons to the unoccupied nl (n = 4, 5; = s, p, d, f) shells of Ni-, Cu-, and Zn-like Au ions. These atomic data are very important for simulating the spectra of the Au plasma and inferring the average charge state of the Au plasma.Finally, some summarization and a vista of the future work have been given in Chapter 8.