3S-CORE AND 3P-CORE LEVEL EXCITATIONS IN 3D-TRANSITION METAL-OXIDES FROM ELECTRON-ENERGY-LOSS SPECTROSCOPY

3s- and 3p-core level excitations for a large number of 3d-transition metal oxides, with a formal 3d occupation from 3d(0) to 3d(10), have b een measured by electron energy loss spectroscopy in reflection geomet ry (REELS) with primary energies 200 eV less than or equal to E(0) les s than or equal to 1600 eV. Their intensities decrease systematically with the formal 3d-count, classifying them as transitions to empty 3d- states. The structure of the 3s excitations is analysed in detail and is compared to the 3s-XPS photoemission spectra of the samples. This 3 s-REELS structure and its change with the 3d occupation can be explain ed by the assumption that the excitation arises mainly from a 3s(2)3d( n) --> 3s(1)3d(n+1) quadrupole transition.