X-ray photoelectron spectroscopic study of perovskite titanates and related compounds: An example of the effect of polarization on chemical shifts

The differences of the binding energy of the Ti 2P_{$\text{3}\text{2}$} electrons obtained by X-ray photoelectron spectroscopy in various perovskite type titanates and related compounds have been studied. The titanium compounds studied were titanium dioxide (anatase and rutile), calcium titanate, strontium titanate, lead titanate and barium titanate. The oxidation number of the titanium ion for all of these compounds is formally 4+. However, the X-ray photoelectron spectra show small shifts in the Ti 2p_{$\text{3}\text{2}$} binding energy as the cation is varied. An analysis of data led to the conclusion that this shift is mainly due to differences in polarization energy between these compounds.