Linear dichroism of the $4f$ photoemission in the giant resonance of atomic europium

The linear dichroism in the $4f$ photoelectron spectra of atomic Eu excited at photon energies in the range of the giant $4d-4f$ resonance have been determined. Dramatic changes of the dichroism have been observed when tuning the photon energy through the giant resonance. The dichroism patterns are compared to the predictions of a model based on LS coupling which takes the interaction of the discrete resonances with the ionization continua into account.