Atoms as many-body systems

The author considers atoms as quantum mechanical many-body systems. In this connection he discusses the HF approximation, the RPA with exchange, and some approaches beyond this RPA. Then he describes the creation of two-electron-two-vacancy states and the multielectron ionization by a single photon. He presents some results on the photoionization of the 4d10 shell in La, the 1s2 shell in Ar, and the 4d10 subshell in Ba. Then he considers the decay of vacancies and configuration mixing. Thereafter he discusses the photon emission in collision processes. Then he describes the elastic scattering and formation of negative ions in this connection, whereby HF results on elastic electron scattering from Xe are presented. (HSI)