Extending Resonant Inelastic X-ray Scattering to Extreme Ultraviolet.

We present α-Al2O3 XAS, XES and RIXS measurements across the Al L2/L3 edges at about 79 eV excitation energy. In the emission spectra, we identify two fluorescence peaks, corresponding to electronic transitions into the 2p core hole from mixed states of Al 3s and Al 3d character, both mixed with O 2p orbitals. Even if the XAS spectrum shows more than one resonance, surprisingly only one clear RIXS signal with energy loss equal to 10.7 eV is present in the data. Nevertheless, this allows us to tentatively extract from the measured high-resolution data the linewidths for fluorescence and RIXS transitions, with the latter being almost a factor of two smaller than the former.