Resonant X-ray emission spectra of K2Ni(CN)4 x H2O at the Ni K-edge.
Resonant X-ray emission spectra were measured at the Ni K-edge for a planar low-spin nickel complex K2Ni(CN)4 x H2O. In the Ni Kbeta emission spectra, a resonant X-ray Raman scattering was observed in the pre-edge region, showing linear energy dispersion of the emitted photon with the incident photon energy. No energy loss features corresponding to the ligand-to-metal charge-transfer (LMCT) was identified. The LMCT feature is characteristic of strongly correlated systems such as NiO; therefore, the LMCT effect proves to be significantly suppressed. This is consistent considering strong covalent character between low-lying pi* ligand and metal 3d (occupied) orbitals in low-spin nickel complexes.