X-ray MnKβemission spectra of manganese oxides and manganates

X-ray Mn $K\beta$ emission spectra of metallic manganese, MnO, ${\mathrm{MnO}}_2$, ${\mathrm{K}}_2$Mn${\mathrm{O}}_4$, and ${\mathrm{KMnO}}_4$ are accurately measured by the fluoresecent excitation method using a two-crystal spectrometer. The results show that molecular-orbital theory provides a suitable interpretation for x-ray $K\beta$ emission spectra of the manganese oxides and manganates. The valence bands of the manganates are mainly composed of the $4p(\pi ,\sigma )$ characters of the molecular orbitals for tetrahedrally coordinated ${\mathrm{MnO}}_4^{-}$, while the valence bands of the manganese oxides are composed of mainly the $4p\left(\pi \right)$ and $4p\left(\sigma \right)$ characters, and also the $3d(\pi ,\sigma )$ characters of the molecular orbitals for octahedrally coordinated oxides. These characters give rise to the structures in the valence band of the manganese oxides. The peak $A$, which is observed in the spectra of the manganese compounds, is ascribed to the transition of mainly $1t_2 or t_{1u}\left({\sigma }_S\right)\to 1s$. The manganates exhibit a simple $K{\beta }_{1,3\mathrm{}}$ peak, while the manganese oxides show a pronounced $K{\beta }^{\prime }$ line. It is understood according to Tsutsumi's proposal on the origin of the $K{\beta }^{\prime }$ line.