Complementary Roles of Co 2p X-Ray Absorption and Photoemission Spectra in CoO

We investigate the Co 2p core-level X-ray absorption (XAS) and photoemission spectra (XPS) in CoO on the basis of a CoO6 cluster model, where Co 3d-O 2p hybridization and multiplet coupling are fully taken into account. We pay particular attention to the effects of multiplet coupling on the XPS and those of Co 3d-O 2p hybridization on the XAS, because those points have been disregarded in the analyses made so far by many authors. From the combined analysis, we show that the XPS and XAS provide us with complementary information on the electronic states of CoO.