SHELL STRUCTURE IN FACETED METAL-CLUSTERS

We study the quantized electronic energy levels in a three-dimensional icosahedral billiard modeling a faceted metal cluster. The first 2000 levels are determined numerically. The magic numbers are compared wit h experimental data and with the results for a spherical model. We dis cuss the supershell structure and propose its study as a test of clust er sphericity. We compare our results with the predictions of the semi classical trace formula and point out the relevance of diffractive orb its.