| Popis: |
We review some properties of metal microclusters in which one observes an interplay between the quantum shell structure of delocalized valence electrons and the ionic framework.1 In particular, we point out that even in systems which are strongly disordered by conventional solid-state criteria (mixed, or alloyed, clusters, clusters with impurities) the existence of quantized shells keeps the spectral features ordered and understood. We discuss the transition from electronic to lattice-based periodicities in cluster growth, and the splittings of giant dipole photoabsorption peaks of clusters. In both cases a reduction in conventional structural order, e. g., by heating, does not lead to a disorganized situation. On the contrary, it allows electronic shell effects to emerge more clearly. Thus metallic clusters are nanoscale systems in which both a distinct shell-based ordering principle and its interplay with the geometric degrees of freedom can be observed. We also comment on recent work addressing the possibility of electron pairing in size-quantized particles. |
