Occupied-states spectroscopy of magnetic systems with circular emission dichroism: The intensity sum rule and the meaning of the measurements

The emission dichroism in resonant valence scattering at the crossing of core edges can give information on occupied valence states of magnetic systems. This information is accessible also when the sample is excited in a dichroic manner and one integrates over the polarization degrees of freedom of the scattered beam, by measuring the spectra as a function of the energy of the emitted photons. However, the spectral function depends not only on the magnetic occupied valence states one wants to explore but also on the excitation process. This creates a link with the absorption dichroism so that the results are always deformed with respect to what is expected from mere consideration of the occupied valence states. We discuss the origin of this deformation and we introduce a rationale to interpret the results of the emission experiments. We show that this deformation must always be taken into account and we discuss its dependence on the relevant parameters on the basis of a simple model calculation.