  The progress and the chronology in understanding the influence of electron
correlations on the electronic structure of atoms and the dynamics of atomic
processes are reviewed focusing on benchmark rare-gas atoms. The contributions
and the chronological development of Photon-Induced Fluorescence Spectroscopy
(PIFS), measuring {} dispersed-fluorescence emission cross sections upon
excitation by single photons provided by monochromatized synchrotron radiation
is described. Selected experimental results obtained by complementary
techniques are also discussed for comparison. The basic suites of computer
programs used for the investigation of the many-electron effects in atoms and
the obtained results are analyzed. Special attention is paid to the
Configuration Interaction Pauli-Fock approximation with Core Polarization
(CIPFCP) method used to interpret the PIFS data.
