Quantum chaos, statistical equilibrium and resonant radiative capture of   electrons by multicharged ions: Au 24+
  We show that the spectrum and eigenstates of open-shell multicharged atomic ions near the ionization threshold are chaotic, as a result of extremely high level densities of multiply excited electron states (1000 levels per eV in Au 24+) and a strong configuration mixing. This complexity enables one to use statistical methods to analyze the system. The orbital occupation numbers obey the Fermi-Dirac distribution, and temperature can be introduced. We show that radiative capture of electrons through the multielectron resonant states is strongly enhanced compared to the direct radiative recombination. 
G. F. Gribakin, A. A. Gribakina, and V. V. Flambaum (School of   Physics, The University of New South Wales, Sydney, Australia)