ELECTRONIC 2P-3D-3S(-1) RESONANT RAMAN-SCATTERING IN 3D TRANSITION-METAL SYSTEMS

We present Resonant Raman Scattering results with a final-state 3s hol e excited across the L-3 threshold in NiO and elemental Co. In NiO the spectra are drastically dependent on the excitation energy while this is not the case in Co. This comes from the different correlation prop erties of the two systems. In particular the NiO results show the fina l state exchange interaction of the 3d(9)3s(1) ionic configuration. Ho wever the NiO spectra excited several eV above the L-3 threshold can b e interpreted in a localized picture only if the relaxation in the int ermediate excited state is also considered. The relaxation process con verts the excited 2p(5)3d(9) configuration to the 2p(5)3d(9) configura tion which would be obtained with threshold excitation. We suggest tha t this relaxation is mostly due to the creation of electron-hole pairs across the gap.