Regensburg 2002 – scientific programme
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O: Oberflächenphysik
O 26: Postersitzung (Rastersondentechniken, Nanostrukturen, Teilchen und Cluster, Methodisches, Oxide und Isolatoren, Grenzfl
äche fest-flüssig, Struktur und Dynamik reiner Oberfl
ächen, Oberfl
ächenreaktionen, Zeitaufg. Spektroskopie, Phasenüberg
änge
O 26.37: Poster
Wednesday, March 13, 2002, 14:30–17:30, Bereich C
Non-Dipolar Effects in X-Ray Photoelectron Spectroscopy — •S. Sellner1,2, F. Schreiber1,2, A. C. Dürr1,2, H. Dosch1,2, I. A. Vartanyants2,3, B. C. C. Cowie4, and J. Zegenhagen4 — 1Institut für Theoretische und Angewandte Physik, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany — 2Max-Planck-Institut für Metallforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany — 3Department for Physics, University of Illinois, Urbana, IL 61801, USA — 4ESRF, B.P. 220, F-38043 Grenoble Cedex, France
X-ray photoelectron spectroscopy (XPS) is usually
analyzed in the dipole approximation. This assumes
that the X-ray wavelength, λ, is much larger
than the radius, re, of the shell of the electron
which is being excited.
However, for high excitation energies and small binding energies,
the condition λ ≫ re is not necessarily
fulfilled.
Using an X-ray standing wave (XSW) field as the source
for excitation, we show how to determine both the
magnitude and the phase of the
lowest-order non-dipolar (quadrupole) contributions
to the XPS cross-section.
We find that these contributions can be significant
and that they have to be included in a quantitative
analysis in certain cases [1].
Specifically, we discuss the implications for the
analysis of XSW data.
[1] F. Schreiber et al., Surf. Sci. Lett. 486 (2001) 519