Theoretical Research On Process Of Excitation And Ionization In Electron-Complicated Atoms Scattering

The breakthrough of high technology depends on our understanding of the rules of electron's movement and the interactions between electrons. It's major character of atomic and molecular physics that explains the basic rules of physics, and explores matters' structures and their evolvements in atomic and molecular level. Most matters consist of complicated atoms whose electrons interact strongly inside. So it's very meaningful to study electrons impact on complicated atoms. It's one of the most powerful methods that explorers problems of many - body systems. Furthermore, methods and technologies created by atomic and molecular physicists can always be used by many other subjects, such as chemistry, astrophysics, biology and so on. Data from electron - complicated atoms are very useful for other subjects, and extremely needed. In this situation, we have improved two theories to study process of excitation and ionization in electron– complicated atoms scattering in this thesis.Couple channel optical (CCO) method has been improved in first part of this thesis. We use m– scheme density matrix to describe the complicated open– shell structure of atomic oxygen target, and the continuum states of target are included in the coupled integral equation with an ab intito complex optical potential in second quantization. We have applied this method to calculate ionization cross sections from threshold of oxygen to 300eV, and the results have shown good agreement with experimental data and other theoretical results, which proves that present optical potential is capable to describe the continuum states of target correctly. After that, we have calculated differential and integral cross sections (DCS and ICS) of 2p4 3P ? 2p33s 3So transition from 15eV to 100eV, and ICS of 2p4 3P ? 2p33d 3D transition from 15eV to 100eV. All of these theoretical results give excellent agreement with experimental data. When calculating DCS and ICS of 2p4 3P ? 2p33s 3So transition, we employ three kinds of target models to explore the effects of discrete and continuum states. As a result, we find that the higher discrete channels have important effects on DCS and ICS in the low intermediate energy region, and continuum states are very important in the entire intermediate energy region. We also have calculated total cross sections (TCS) and partial wave cross sections (PWCS) to explore resonances in electron– oxygen scattering. Former experimental data have been reproduced successfully, and some new points of resonances have been found by comparing TCS with PWCS. More experimental and theoretical researches are needed to support our results.Later, we have tried to improve distorted wave Born approximation (DWBA) method to study process of ionization in electron– atom scattering which is called (e, 2e) reaction. We choose the complicated close– shell atomic Argon (3p) as target. Considering the importance of continuum states and strong polarization effect on slow ejected electron, we have employed optical potential mentioned before to describe the continuum channels of slow electron, and used an imaginary potential to describe its discrete channels. Using this method, we have calculated triple differential cross sections of 3p orbital (e,2e) reaction of Ar in 721eV in which the energy of fast scattered electron and slow ejected electron are 500eV and 250eV respectively and the fast scattered electron is fixed at 3°. This is completely a new case of (e, 2e) reaction, in which energy loss is large (about one third of the incident energy) and momentum transfer, which is 1.27 a.u., is close to its minimum value 1.22 a.u. (this value is reached when the scattering angle is 0°). Comparing with original DWBA calculations and experimental data, our present calculations of triple differential cross sections is higher than original DWBA method. It means that with optical potentials in slow electron can improve original DWBA method. The binary peak in small angles seems still a lot higher than experimental data. However, more experimental data are needed in small angles to confirm the exact situation. Generally speaking, binary peak and recoil peak are shown in momentum transfer direction K? and its negative direction ? K? respectively, which coincides with former experiences in outer shell (e, 2e) reaction. Furthermore, an appropriate model potential is to be built in the next to simulate the strong interactions, such as polarization, autoionization, and so on, between slow electron and the other five electrons in outer shell of residual Argon ion.