Information of valence charge of 3d transition metal elements observed in L-emission spectra

L-emission spectra of 3d transition metal elements from Sc to Zn and some oxides were measured to examine the relation between L-emission intensities of Lα, Lβ, Lℓ, and Lη and valences of those elements by using a soft X-ray emission spectrometer attached to a scanning electron microscope. Lα,β emission intensity due to transitions from valence bands to core 2p levels compared with Lℓ,η emission intensity due to transitions from core 3 s to deeper 2p levels, Lα,β/Lℓ,η was found to be a key parameter. A linear relation was found between the number of 3d electrons and the intensity ratio of Lα,β/(Lα,β+ Lℓ,η) from Sc to Ni, except for Cr. It takes into account not only a change in N3d but also a change of transition probability due to a change in N3d In the case of 3d metal oxides, the evaluation based on the equation showed an overestimation of the calculated number of 3d electrons, which could be due to a charge transfer from ligand oxygen atoms to the transition metal element, resulting from a core-hole effect in the intermediate state.