  Closed analytical formulas are derived for the differential and total cross
sections of the non-relativistic photoelectric effect in the three main classes
of few-electron atomic systems: (1) neutral atoms and positively charged atomic
ions which contain more than one bound electron, (2) negatively charged atomic
ions, and (3) one-electron atoms and ions. Our procedure developed in this
study is a combination of QED methods and results of the density functional
theory obtained for atoms and ions. In all these systems the photoelectric
effect is considered as photodetachment of the outer-most electron and our
analysis is based on the results of density functional theory obtained for the
electron density (radial) distribution in these atomic systems. Analytical
formulas (similar to ours) for the differential and total cross sections of
photoelectric effect for atomic systems from classes (1) and (2) have never
been produced in earlier studies.
