Fano antiresonance in the excitation spectra of the luminescence of divalent europium

In the excitation spectra of the luminescence of Eu²⁺-doped compounds features are observed which are interpreted as Fano antiresonance lines due to interaction between the 4f⁷{(}⁶IJ{,}⁶DJ) states and the 4f⁶5d states. The observations can be understood on the basis of results from two-photon absorption experiments on Eu²⁺.