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Geometric and electronic tructure of large sodium cluster anions
Michael Moseler 1,2 , Bernd Huber 2 ,B. von Issendorff 3
1 Fraunhofer Institut für Werkstoffmechanik, Wöhlerstrasse 11, 79108 Freiburg, Germany
2 Freiburger Materialforschungszentrum , Stefan-Meier-Strasse 21, 79104 Freiburg, Germany
3 Fakultät für Physik, Universität Freiburg, Stefan-Meier-Str. 21, 79104 Freiburg, Germany
A - 9
Photoelectron spectroscopy is a frequently used experimental method to extract electronic
binding energies from atomic, molecular, and condensed-matter systems. For molecules and
clusters at low temperature, a comparison of the measured photoelectron spectra (PES) with the
electronic density of states (DOS) obtained from density functional calculations for T=0 optimal
structures, provides information about the underlying electronic structure and may lead to
assignments of pertinent structures.
For the range of N=4-19 the PES of NaN - clusters were compared with the DOS recorded in our
finite-temperature ab initio simulations [1]. Although the main features of the PES can be
understood through the use of the jellium model, we are able to detect and explain several
spectral details caused by the finite temperature dynamics. Meanwhile experimental spectra
from very cold cluster beams are available and a comparison with T=0 static spectra reveals
new information concerning the ground states of the clusters.
Also larger sodium cluster anions have been measured and simulated by us. For Na55 -, Na147 -
and Na309 - the DOS of Mackay-icosahedral clusters was in good agreement with the
corresponding PES (see Fig. 1) and for Na71 - a clear difference between the DOS of an anti-
Mackay and an Mackay over layer has been detected.
References
Figure 1. Comparision of the Na309 - PES and the DOS of the Mackay-icosahedron.
[1] M. Moseler, B. Huber, H. Häkkinen, U. Landman, G. Wrigge, M. Astruc Hoffmann and B. von
Issendorff, Phys. Rev. B 68, 165413 (2003).
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