Kondo-like 4f delocalization in Gd at high pressure

We present resonant inelastic x-ray scattering (RIXS) and x-ray emission spectroscopy (XES) results which suggest Kondo-like aspects in the delocalization of 4f electrons in Gd metal to 113 GPa. Analysis of the RIXS data reveal a prolonged and continuous process throughout the entire pressure range, so that the volume collapse transition at 59 GPa is only part of the delocalization phenomenon. Moreover, the Lγ1 XES spectra indicate no apparent change in the bare 4f moment across the collapse, suggesting that Kondo screening is responsible for the expected Pauli-like behavior in magnetic susceptibility.