Role of Rotational Tunneling in the Metastable Decay of Rare Gas Cluster Ions

摘要

The dissociation of cluster ions that occurs following the ionization of neutral aggregates formed in supersonic expansions has been the subject of extensive interest during recent years. Although earlier workers attempted to draw a one-to-one correspondence between the clusters observed mass spectrometrically (requiring ionization for mass selection and detection) and the preexisting neutral cluster distribution, the significance of cluster fragmentation has now become well documented for a wide variety of chemically different systems and for different ionization techniques including electron impact and photoionization. More recently interest has centered on factors governing the origin of magic numbers, and particularly on the mechanisms and rates of the ensuring dissociation which follows the ionization of clusters. Several researchers have considered reasons for the magnitudes of the metastable rates observed in the various experiments. Klots pointed out that evaporative dissociation processes lead to concomitant changes in the internal energy of an ensemble of dissociating clusters. Reprints. (JES)