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O: Oberflächenphysik

O 4: Elektronische Struktur I

O 4.5: Talk

Monday, March 24, 2003, 12:15–12:30, FOE/ANOR

Resonant inelastic x-ray scattering (RIXS) and NEXAFS investigations on organic materials — •O. Fuchs¹, L. Weinhardt¹, C. Heske¹, E. Umbach¹, Y. Zubavichus², M. Grunze², J.D. Denlinger³, Z. Hussain³, and R. Follath⁴ — ¹Exp. Physik II, Uni Würzburg — ²Angew. physikal. Chemie, Uni Heidelberg — ³Lawrence Berkeley National Lab — ⁴BESSY GmbH, Berlin

RIXS is a “photon-in-photon-out” process and therefore — unlike electron spectroscopies — a bulk sensitive method for the study of the electronic structure of matter. In combination with fluorescence-yield NEXAFS (near- edge x-ray absorption fine structure), occupied as well as unoccupied electronic states can be investigated. For well-ordered samples, angle resolved RIXS and NEXAFS measurements yield additional information about the orientation of electronic orbitals. Since both techniques can be applied through a thin membrane (e.g. a silicon nitride window), it is even possible to study biological molecules in their natural aqueous environment.

A third-generation synchrotron and a highly efficient spectrometer for soft x-rays are essential for RIXS. This talk presents a new grating spectrometer design for the sulfur L_2,3, carbon K, nitrogen K, and oxygen K edges dedicated to the study of biologically relevant molecules. Furthermore, RIXS and NEXAFS measurements of polycrystalline amino acids and angle resolved studies of ordered PTCDA multilayers are presented. The measurements were performed at beamline 8.0.1 of the Advanced Light Source (Berkeley, California), and at the U41-PGM of BESSY II (Berlin).