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 me asured using electron energy-loss spectroscopy (EELS) and are analyzed usin g the ab initio full multiple-scattering (MS) calculations. The near-edge s tructures arise mainly from covalency by direct and/or indirect interaction between oxygen and metal. The coordination number of the cation and the si te symmetry also influence the spectral shape and structures. Comparison of full MS simulations of different clusters around the excited atom allows t o interpret and correlate the features present in the spectra of each compo und to its specific atomic arrangement and electronic structure.