Comment on “Resonant inelastic x-ray scattering of MnO: $L_{2,3}$ edge measurements and assessment of their interpretation”

Recently, Ghiringhelli et al. [Phys. Rev. B 73, 035111 (2006)] reported on the $d\text{−}d$ crystal field and charge-transfer excitations in MnO by using resonant inelastic x-ray scattering (RIXS). The data were analyzed with the single impurity Anderson model (SIAM) as well as with the crystal-field model (CFM), with both models providing very different parameters. The results of their CFM analysis are in conflict with the results obtained by analyzing electron-energy-loss spectroscopy (EELS) data with the same model.

Figure 1

EEL spectrum of MnO/Ag(001), taken along the (110) axis in off-specular scattering geometry at a primary energy $E_0=28\text{eV}$ (FWHM 250 meV), compared to the Tanabe-Sugano diagram for the $3d^5$ configuration of ${\text{Mn}}^{2+}$, calculated from the matrices listed in Ref. 9. Black dots: energy losses of the EEL spectrum on MnO; black squares: energies of the ${}^{2S+1}L$ multiplets of the free ${\text{Mn}}^{2+}$ ion (i.e., center of gravity of the ${{}^{2S+1}L}_{\left|L+S\right|\dots \left|L-S\right|}$ levels from Ref. 10). The ${{}^{4}T}_{1g}\left({}^{4}F\right)$ and ${{}^{4}T}_{2g}\left({}^{4}F\right)$ terms (dotted lines) were not observed in the EELS data.