The core-level x-ray photoemission spectroscopy (XPS) satellites of single-crystalline ${\mathrm{SrTiO}}_3,$ ${\mathrm{SrTiO}}_3:\mathrm{La},$ and ${\mathrm{SrTiO}}_3:\mathrm{Nb}$ in situ fractured in ultrahigh vacuum were compared with the electron-energy-loss spectrum and theoretical electron-energy-loss functions from first-principles electronic structure calculations. Experimental core-level XPS satellites of O $1s$ can be represented by peaks positioned at 6.1, 11.7, 14.2, 17.2, 19.7, 27.4, and 30.6 eV. The prominent features of theoretical electron-energy-loss functions agreed with those in the experimental satellites except the peaks around 20 eV.

• Received 14 January 2000

DOI:https://doi.org/10.1103/PhysRevB.62.7964