X-Ray absorption and resonant inelastic x-ray scattering (RIXS) show the presence of Cr~+ at the surface and in the bulk of CrF_2.

摘要

X-Ray absorption and resonant inelastic x-ray scattering (RIXS) spectra of CrF2 recorded at the chromium L_(2,3) are presented. An atomic multiplet crystal field calculation is compared with the experimental data. Experiment and theory are in agreement once the calculation includes three chromium oxidation states, namely Cr~+, Cr~(2+), and Cr~(3+). X-Ray absorption allows a direct determination of the surface oxidation, while the RIXS spectra shows the presence of these three oxidation states in the sample bulk. To give a quantitative interpretation of the RIXS data the effect of the incomming and outgoing photon penetration depth and self-absorption must be considered. For the much simpler case of MnF2, with only one metal oxidation state, the measured RIXS spectra relative intensities are found to be proportional to the square of the sample attenuation length.