DENSITY-FUNCTIONAL THEORY OF THE COLLECTIVE ELECTRONIC EXCITATIONS INNANKN CLUSTERS

The collective electronic response of NanKn clusters has been studied for some model structures. In their low-temperature lowest-energy stru cture, those clusters have all the K atoms on the surface. The collect ive oscillation frequencies for clusters with the K atoms segregated t o the surface are red-shifted with respect to the corresponding freque ncies for isomers with a very similar underlying skeleton but with the Na atoms segregated to the surface. The collective frequency varies s moothly with respect to the degree of relative segregation. These resu lts may be useful in the analysis of the collective response of large alloy clusters and microcrystals. (C) 1995 John Wiley & Sons, Inc.