Analysis of the odd-even alternation in simple metal clusters

A set of MO-LCAO calculations within the LSDA formalism has been performed for the analysis of the odd-even alternation in simple metal clusters. Electronic properties, including ionization potentials and partial density of states analyses were evaluated for clusters of Na, K, Cu and Ag ranging from two to nine atoms. The present study focus on the differences in magnitude of the odd-even alternation, which is attributed to the electronic level separation close to the Fermi level of the clusters. For the coinage metals, the hybridization between s, d and p states is shown to strongly influence the alternation, reducing the magnitude for copper to about the same value as for silver. The small reduction of the alternation magnitude due to a finite spin density for the odd clusters is also investigated by means of comparative LDA calculations.