Abstract
Intensity anomalies (magic numbers) have been observed in the mass spectra of sodium clusters containing up to 22 000 atoms. For small clusters (Na n ,n≤1500) the anomalies appear to be due to the filling of electronic shells (groups of subshells having the same energy). The shells can be characterized rather well by a pseudoquantum-number, indicating the possible existence of a symmetry higher than spherical. The mass spectra of larger clusters (1500≤n≤22 000) are well explained by the completion of icosahedral or cuboctahedral shells of atoms. The fact that the two types of shells (electron and atom) occur in distinct and non-overlapping size intervals might indicate the existence of a “liquid” to “solid” transition in going from small to large clusters.
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References
Knight, W.D., Clemenger, K., de Heer, W.A., Saunders, W.A., Chou, M.Y., Cohen, M.L.: Phys. Rev. Lett.52 2141 (1984)
Kappes, M.M., Kunz, R.W., Schumacher, E.: Chem. Phys. Lett.91 413 (1982)
Katakuse, I., Ichihara, I., Fujita, Y., Matsuo, T., Sakurai, T., Matsuda, T.: Int. J. Mass Spectrom. Ion Processes67 229 (1985)
Brechignac, C., Cahuzac, Ph., Roux, J.-Ph.: Chem. Phys. Lett.127 445 (1986)
Begemann, W., Dreihofer, S., Meiwes-Broer, K.H., Lutz, H.O.: Z. Phys. D-Atoms, Molecules and Clusters3 183 (1986)
Saunders, W.A., Clemenger, K., de Heer, W.A., Knight, W.D.: Phys. Rev.B32 1366 (1986)
Bergmann, T., Limberger, H., Martin, T.P.: Phys. Rev. Lett.60 1767 (1988)
Martins, J.L., Car, R., Buttet, J.: Surf. Sci.106 265 (1981)
Ekardt, W.: Ber. Bunsenges. Phys. Chem.88 289 (1984)
Clemenger, K.: Phys. Rev.B32 1359 (1985)
Ishii, Y., Ohnishi, S., Sugano, S.: Phys. Rev.B33 5271 (1986)
Bergmann, T., Martin, T.P.: J. Chem. Phys.90 2848 (1989)
Göhlich, H., Lange, T., Bergmann, T., Martin, T.P.: Phys. Rev. Lett.65 748 (1990)
Martin, T.P., Bergmann, T., Goehlich, H., Lange, T.: Chem. Phys. Lett.172 209 (1990)
Bjørnholm, S., Borggreen, J., Echt, O., Hansen, K., Pedersen, J., Rasmussen, H.D.: Phys. Rev. Lett.65 1627 (1990)
Persson, J.L., Whetten, R.L., Cheng, H.P., Berry, R.S.: (to be published)
Echt, O., Sattler, K., Recknagel, E.: Phys. Rev. Lett.47, 1121 (1981)
Farges, J., de Feraudy, M.F., Raoult, B., Torchet, G.: J. Chem. Phys.84 3491 (1986)
Northby, J.A.: J. Chem. Phys.87 6166 (1987)
Lethbridge, P.G., Stace, A.J.: J. Chem. Phys.91 7685 (1989)
Miehle, W., Kandler, O., Leisner, T., Echt, O.: J. Chem. Phys.91 5940 (1989)
The subject of icosahedral shells of atoms in inert gas clusters has a long and interesting history. For a recent starting point into this extensive literature see: Proceedings of Faraday Symposium on Large Gas Phase Clusters. J. Chem. Soc. Faraday Trans.86 (1990)
Bergmann, T., Martin, T.P., Schaber, H.: Rev. Sci. Instrum.60 347 (1989);60, 792 (1989)
Bergmann, T., Göhlich, H., Martin, T.P., Schaber, H., Malegiannakis, G.: Rev. Sci. Instrum.61 2585 (1990)
Bohr, A., Mottelson, B.R.: Nuclear structure. London: Benjamin 1975
Nishioka, H. Hansen, K. Mottelson, B.R.: Phys. Rev.B (to be published)
Balian, R., Bloch, C.: Ann. Phys.69 76 (1971)
Mackay, A.L.: Acta. Cryst.15 916 (1962)