STUDY OF ELECTRON IMPACT EXCITATION OF ATOMS AND THEIR DECAY

Abstract

In recent years, there has been considerable progress in the study of various electron-impact excitation processes of relatively heavier atoms, both theoretically and experimentally. This is due to the advances in the quality of experimental technology through which sophisticated experiments have been possible. Such experiments consequently lead to the development of powerful theoretical models. For example, with the introduction of electron-photon-coincidence technique it has been possible to get additional information about the dynamics of the electron-atom excitation process than the one obtained through traditional differential and total cross section measurements. Similarly the experiments involving super-elastic scattering from the laser excited atoms can provide even better information than the electron-photon coincidence method. Although the principle involved in the super-elastic experiment and the electron-photon coincidence technique is of reverse nature. We know, with such experiments, alignment and orientation of the excited atom can be easily determined. Further, the ease with which production and detection of spin polarized electrons have become possible, a new dimension has now been added to the exploration of atomic forces viz. the spin dependent electron exchange and spin-orbit interactions. The analysis of spin-polarization of the scattered electrons after the excitation process is also an important experimental technique to study the electron impact excitation processes. Seven independent parameters, called generalized STU parameters, can be measured in such experiments. The experimental determination of the generalized STU parameters requires the knowledge of the incident electron beam spin polarization and the detection of spin polarization of the scattered Chapter-3: Relativistic distorted wave method has been applied to the electron impact excitation of argon atom to study the transitions from the ground state to the excited 4s[3 / 21°2, 4s[3 / 21°, , 4s' [1 / 2]°0 and 4s' [1/ 21°1 states.