Doping dependence of Ni 2p x-ray-absorption spectra of MxNi1−xO (M=Li,Na)

In this paper we give a description of the doping dependence of the Ni 2p x-ray-absorption spectra of MxNi1−xO (M=Li,Na). We will show that a description beyond an atomic-multiplet calculation is required. To study intermediate doping levels use will be made of a two-metal-site cluster, where one side functions as a hole reservoir. From this study it follows that holes are most likely on the oxygen atoms of the NiO6 units around the Li impuritie