Resonant inelastic x-ray scattering in electronically   quasi-zero-dimensional CuB2O4
  We explore the general phenomenology of resonant inelastic scattering (RIXS) using CuB2O4, a network of CuO4 plaquettes electronically isolated by B+3 ions. Spectra show a small number of well-separated features, and we exploit the simple electronic structure to explore RIXS phenomenology by developing a calculation which allows for intermediate-state effects ignored in standard approaches. These effects are found to be non-negligible and good correspondence between our model and experiment leads to a simple picture of such phenomenology as the genesis of d-d excitations at the K edge and intermediate-state interference effects. 
J. N. Hancock, G. Chabot-Couture, Y. Li, G. Petrakovskii, K. Ishii, I.   Jarrige, J. Mizuki, T. P. Devereaux, M. Greven