Volume 81, Number 2, January 2008
Article Number 26004
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 07 December 2007
EPL, 81 (2008) 26004
DOI: 10.1209/0295-5075/81/26004

High multipole transitions in NIXS: Valence and hybridization in 4f systems

R. A. Gordon1, G. T. Seidler2, T. T. Fister2, M. W. Haverkort3, G. A. Sawatzky4, A. Tanaka5 and T. K. Sham6

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

received 10 October 2007; accepted in final form 19 November 2007; published January 2008
published online 7 December 2007

Momentum-transfer (q) dependent non-resonant inelastic X-ray scattering measurements were made at the N4, 5 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 4f 0 and 4f 1 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 4f 0-related multiplet features. We expect such strong, non-dipole features to be generic for NIXS from f-electron systems.

PACS - X-ray scattering (including small-angle scattering).
78.20.Bh - Theory, models, and numerical simulation.
61.05.cj - X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.

© EPLA 2008