Oxygen 1s ELNES study of perovskites (Ca,Sr,Ba)TiO3.

The O K-edge spectra of perovskites XTiO3 with X=Ca, Sr and Ba have been measured using electron energy-loss spectroscopy (EELS) and are analyzed using the ab initio full multiple-scattering (MS) calculations. The near-edge structures arise mainly from covalency by direct and/or indirect interaction between oxygen and metal. The coordination number of the cation and the site symmetry also influence the spectral shape and structures. Comparison of full MS simulations of different clusters around the excited atom allows to interpret and correlate the features present in the spectra of each compound to its specific atomic arrangement and electronic structure.