Magic Numbers in Atomic Clusters: Energetic, Electronic and Structural Effects

Abstract

The subject of magic numbers in clusters has been one of long-standing interest since early observation of pronounced intensity anomalies seen in the mass spectral distributions of molecular and atomic systems (1–10). Early observations in the case of water (2,3)revealed a particularly stable entity involving 21 molecules bound to a proton, which was first seen in the electron impact ionization of neutral water clusters, and later in proton expansion experiments and upon the bombardment of ice surfaces with fast atomic ions (11). The underlying commonality strongly pointed to the origin of magic numbers involving a particularly stable ion, a fact which has recently been proven (12–15). During the last decade there has been extensive experimental and theoretical interest in atomic systems (6,7,15–18), particularly for clusters of rare gas atoms and those involving metallic-type constituents. In view of the fact that the magic number patterns observed in the case of rare gas clusters coincided almost exactly with compact structures calculated for the neutrals, they were first interpreted in terms of especially stable neutral aggregates, despite the fact that fragmentation could obviously play a role following the ionization and concomitant fragmentation often involved.KeywordsMagic NumberCluster SystemJellium ModelMetastable DecayAluminum AnionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.