We present a rigorous parameter-free theoretical treatment of the Ce 4s and 5s photoelectron spectra of CeO2. The currently accepted model explains the satellite structure in the photoelectron spectra in terms of mixed valence (Ce 4f(0) O 2p(6), Ce 4f(1) O 2p(5), and Ce 4f(2) O 2p(4)) configurations. We show that charge transfer (CT) into Ce 5d as well as configurations involving intra-atomic movement of charge must be considered in addition and compute their contributions to the spectra. (C) 2010 Elsevier B.V. All rights reserved.