  Highly excited eigenstates of atoms and ions with open f shell are chaotic
superpositions of thousands, or even millions of Hartree-Fock determinant
states. The interaction between dielectronic and multielectronic configurations
leads to the broadening of dielectronic recombination resonances and relative
enhancement of photon emission due to opening of thousands of radiative decay
channels. The radiative yield is close to 100% for electron energy . 1 eV and
rapidly decreases for higher energies due to opening of many autoionization
channels. The same mechanism predicts suppression of photoionization and
relative enhancement of the Raman scattering. Results of our calculations of
the recombination rate are in agreement with the experimental data for W20+ and
Au25+.
