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The controlled-valence properties of La& "Sr"Fe03 and La& "Sr"Mn03 are studied by means of softx-ray absorption spectroscopy. A comparison between the transition-metal 2p spectra and atomicmultiplet calculations is used to determine the 3d count. The 0 1s spectrum is used to characterize changes in unoccupied states that contain oxygen p character. The results indicate that the holes induced by substitution for both series are located in states of mixed metal 3d-oxygen 2p character. The ground state of LaFe03 is mainly 3d' and becomes 3d'L (where L denotes a ligand hole) in the Lal "Sr"Fe03 series for low Sr concentration. The main component of the ground state of LaMn03 is 3d and becomes a mixture of 3d' and 3d L in the Lal "Sr"Mn03 series. The trends in controlledvalence properties of similar oxides across the transition-metal series can be rationalized within the framework of the Zaanen-Sawatzky-Allen model.

A detailed investigation of V205, VO2, V~03, and V metal is presented. The vanadium core lines in the x-ray photoelectron spectra are anomalously wide for V203 and VO2. It is shown that this is a consequence of the narrow 3d band in these materials and the relatively strong core-hole 3d Coulomb interaction. The influence of electron correlation effects in the 3d band on the co're linewidths is discussed. The valence bands are compared to band-structure calculations and the difference in the band structure above and below the semiconductor-metal transition is discussed. The Auger results are discussed in terms of the 3d partial density of states. It is found that there is a large amount of d character in the 0-2p region of the valence band, Also the average "on-site" Coulomb interaction of 3d electrons is obtained from the Auger spectra and is discussed in terms of electron correlation effects.

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