Supershells in Metal Clusters
In the mass spectra of elemental clusters one observes oscillations in
the abundance as a function of cluster size. These oscillations reflect
variations \tilde E in the total energy of the clusters. In most cases
\tilde E is determined by the geometric arrangement of the atoms. For simple
metals at temperatures above the melting point, however, the electonic
structure is dominant, giving rise to electonic shells and
supershells.
Using a jellium model for systems of up to 10000 electrons, the
experimental findings for alkali clusters can be reproduced fairly well.
But in the case of gallium that simple model fails. To gain insight into
the mechanisms determining the shell and supershell structure, we extend
the known semiclassical analysis for the DOS of a spherical cavity
to more realistic potentials. This suggests a simple mechanism for explaining
the failure of the jellium model for metals with high electron density.
For an overview, take a look at these Slides
taken form a talk on the subject (1MB)
More detailed information can be found in the following publications

Erik Koch:
Supershells in Metal Clusters: SelfConsistent Calculations and
Their Semiclassical Interpretation
Phys.Rev.Lett 76, 26782681 (1996) and condmat/9606023

Erik Koch:
On the 3n+l Quantum Number in the Cluster Problem
Phys.Rev. A 54, 670676 (1996) and condmat/9606050

Erik Koch and Olle Gunnarsson:
Density Dependence of the Electronic Supershells in the Homogeneous
Jellium Model
Phys.Rev. B 54, 51685177 (1996) and condmat/9606140

Erik Koch:
Periodic Orbit Expansion for Realistic Cluster Potentials
Phys. Rev. B 58, 2329 (1998) and condmat/9803309
Even more information can be found in my PhD thesis
(in German).