The electronic structure of CaMnOx with 2.66<=x<=3.00

We studied the electronic structure of CaMnOx with 2.66 less than or equal to x less than or equal to 3.00 by means of soft X-ray absorption spectroscopy (XAS). The Mn 2p XAS spectra present changes in the shape of the multiplets and chemical shifts. The chemical shifts indicate a decrease of the Mn 3d count as the oxygen content increases. The Mn 2p XAS spectra are calculated projecting the atomic multiplet on the appropriate crystal field. The O 1s XAS spectra show an increase in the absorption intensity just above the bottom of the conduction band. This effect indicates an increase of unoccupied O 2p states for larger oxygen contents. The O 1s XAS spectra are calculated using cluster model calculations which include charge transfer processes. We conclude that the doped holes in the CaMnOx system contain a mixture of metal and ligand character. (C) 1997 Elsevier Science Ltd.