Inelastic X-ray scattering in correlated (Mott) insulators
  We calculate the inelastic light scattering from X-rays, which allows the photon to transfer both energy and momentum to the strongly correlated charge excitations. We find that the charge transfer peak and the low energy peak both broaden and disperse through the Brillouin zone similar to what is seen in experiments in materials like Ca_2 Cu O_2 Cl_2. 
T.P. Devereaux, G.E.D. McCormack, and J.K. Freericks