Configuration interaction in $L_{2,3}$-edge resonant inelastic x-ray scattering spectra of ${\mathrm{CaF}}_2$ and ${\mathrm{ScAl}}_2$

We have measured resonant inelastic x-ray scattering excited at the $L_{2,3}$ edges of Ca and Sc, detecting the filling of the $2p$ core hole by an inner-shell electron. The spectral shape is strongly influenced by the interaction in the final state of the ${3s}^{-1}{3d}^{n+1\mathrm{}}$ and ${3p}^{-2}{3d}^{n+2\mathrm{}}$ configurations as shown by comparing atomic multiplet calculations performed without and with configuration interaction. We show that this interaction causes a strong redistribution of the spectral weight over a wide energy range.