1. Mass spectrometric evidence for icosahedral structure in large rare gas clusters: Ar, Kr, Xe.
- Author
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Miehle, W., Kandler, O., Leisner, T., and Echt, O.
- Subjects
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CLUSTER theory (Nuclear physics) , *ARGON , *KRYPTON , *XENON , *ELECTRON impact ionization - Abstract
Clusters of argon, krypton, and xenon are grown in a free jet and ionized by electron impact. The size of these clusters, (Rg)+n, extends up to n[bar_over_tilde:_approx._equal_to]1000. Individual cluster sizes are mass resolved up to n[bar_over_tilde:_approx._equal_to]570 in the case of Ar+n. The well known, but puzzling differences in the size distributions of Kr and Xe clusters disappear beyond n[bar_over_tilde:_approx._equal_to]130, while those between Ar and Xe disappear beyond n[bar_over_tilde:_approx._equal_to]220. The most pronounced ‘‘magic numbers’’ in the distributions of large cluster ions occur at n=147 (148 for Ar), 309, and 561, in striking agreement with the number of atoms required to build icosahedral clusters with 3, 4, and 5 complete coordination shells, respectively. Closure of the 6th icosahedral coordination shell is indicated by another strong intensity drop at n[bar_over_tilde:_approx._equal_to]923 in the unresolved part of the spectra. Several additional intensity extrema are observed between major shell closures. A simple structural model, assuming an icosahedral core decorated by the additional atoms, accounts for these anomalies reasonably well up to n=561. [ABSTRACT FROM AUTHOR]
- Published
- 1989
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