5f covalency from x-ray resonant Raman spectroscopy.

X-ray resonant Raman spectroscopy (XRRS), a variant of resonant inelastic x-ray scattering, has been used to investigate the two prototype systems, UFand UO. Both are U5fand each is an example of 5f localized, ionic behavior and 5f localized, covalent behavior, respectively. From the MXRRS measurements, the 5f band gap in each can be directly determined and, moreover, a clear and powerful sensitivity to 5f covalency emerges.