High multipole transitions in NIXS: Valence and hybridization in systems

¹  Department of Physics, Simon Fraser University - Burnaby, BC, V5A 1S6, Canada
²  Department of Physics, University of Washington - Seattle, WA, 98105, USA
³  II. Physikalisches institut, Universität zu Köln - Zülpicher Str. 77, D-50937 Köln, Germany
⁴  Department of Physics and Astronomy, University of British Columbia - Vancouver, BC, V6T 1Z1, Canada
⁵  Department of Quantum Matter, ADSM, Hiroshima University - Higashi-Hiroshima 739-8530, Japan
⁶  Department of Chemistry, University of Western Ontario - London, Ontario, N6A 5B7, Canada

Corresponding author: ragordon@sfu.ca

Received: 10 October 2007
Accepted: 19 November 2007

Abstract

Momentum-transfer dependent non-resonant inelastic X-ray scattering measurements were made at the N edges for several rare-earth compounds. With increasing q, giant dipole resonances diminish, to be replaced by strong multiplet lines at lower energy transfer. These multiplets result from two different orders of multipole scattering and are distinct for systems with simple and initial states. A many-body theoretical treatment of the multiplets agrees well with the experimental data on ionic La and Ce phosphate reference compounds. Comparing measurements on CeO₂ and CeRh₃ to the theory and the phosphates indicates sensitivity to hybridization as observed by a broadening of -related multiplet features. We expect such strong, non-dipole features to be generic for NIXS from f-electron systems.