Study of bulk ground state properties of cerium intermetallics by linear dichroism in 4f resonant inelastic X-ray scattering

We have measured polarization effects by 4f resonant inelastic X-ray scattering in the M-5 region of intermetallic compounds of cerium (CeRh2, CePd3, Ce7Rh3, and CeAl2). The experiment was performed using linearly polarized radiation with direction either perpendicular or parallel to the scattering plane. The dichroic effect is strong and depends on the degree of hybridization of the compound. We show that there is a monotonous relationship between the measured dichroism. integrated along the emitted energies, and the radius of the cerium ion in different compounds. Since the atomic size of cerium is directly related to its valence, we conclude that the linear dichroism in inelastic X-ray scattering is a bulk-sensitive indicator of the relative weight of the 4f(0) and 4f(1) ground state configurations of cerium compounds. (C) 2002 Published by Elsevier Science Ltd.