Relativistie Distorted Wave Study On The Electron Impact Excitations Of Argon Atom And Highly Charged Tungsten Ions

Electron impact excitation(EIE) is a basic process in the atomic physics. 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. In this thesis, the influence of electron correlation effects on the neutral Argon atoms and the Breit interaction on high charged W ions of the electron impact excitation process have been investigated systematically.In chapter III, the electron impact excitation cross section from the metastable states 3p~54s to the lowest excited states 3p~54p have been calculated systematically. At present, a number of theoretical and experimental studies have been carried out on the metastable state excitations of argon. However, there are still some big discrepancies between these calculations and experiments because of strong correlation and relativistic effects. To illustrate the electron correlation effects on the cross sections, two correlation models were used to describe the target states in the calculations. The results show that: in low-energy collisions, the correlation effects are relatively large; in the high energy collision, the electron correlation effects are relatively small. The correlation effects make the cross sections smaller, and the calculations are in good agreement with experiments.Chapter IV, electron impact excitation cross sections of argon from the meatstable states of 3p~54s to the high excited states of 3p~55p configuration were calculated, and the influence of electron correlation effects on cross section are discussed in different correlation models in detail. We found that, for the core-preserving(optically allowed) excitations, our results which include correlation effects are in good agreement with experiments; for the core-changing(optically forbidden) excitations, the theoretical results are smaller than the experiments, the reason mainly due to the cascade effects were not take into account in the calculations.Chapter V, Detailed calculations have been carried out for the excitation energy, EIE cross sections and polarization from the occupied 3d electrons to the unoccupied 5f shells of Cu-, Zn-, Ga-, and Ge-W ions, we also study the influence of the Breit interaction on the EIE cross sections and polarization. It is found that, with the increase of incident electron energy, the EIE cross section gradually decreased, the polarization begins to increase and then decrease. The polarization have the max value when the incident electron energy as large again as threshold. The effects of the Breit interaction on the EIE cross sections are very small, but the influence on the polarization is large with the increase of incident electron energy.