Resonant inelastic x-ray scattering in Ni componds

Resonant inelastic x-ray scattering was measured at the Ni K-edge in NiO, N iSO4, NiF2, NiCl2 and NiBr2. The charge-transfer energies from a ligand fie ld to the Ni 3d states of these compounds are obtained directly from the en ergy differences between the elastic and the 4p-->1s inelastic scattering. The sample dependence of the energy shift agrees roughly with the result of a fitting calculation of the 2p-x-ray photoelectron spectroscopy. We obser ved a negative correlation between the energy shift and the intensity ratio of the shoulder to the main peak of the Ni K beta(1,3) emission spectra. B ecause this spectral ratio refers to the number of 3d electrons, the charge -transfer to the 3d states is depressed with increasing charge-transfer ene rgy.