|
|||||
|
|
Magic Numbers in Boson 4He Clusters: The Auger Evaporation Mechanism |
|
| Authors: | Elena Spreafico Giorgio Benedek Oleg Kornilov Jan Peter Toennies |
| Affiliation: | 1.Department of Materials Science, University of Milano-Bicocca, Via R. Cozzi 53, 20125 Milan, Italy;2.Donostia International Physics Center (DIPC), Paseo M. de Lardizàbal 4, 20018 Donostia-San Sebastián, Spain;3.Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany;4.Max-Planck-Institute for Dynamics and Self-Organization, Bunsenstrasse 10, 37073 Göttingen, Germany; |
| Abstract: | The absence of magic numbers in bosonic 4He clusters predicted by all theories since 1984 has been challenged by high-resolution matter-wave diffraction experiments. The observed magic numbers were explained in terms of enhanced growth rates of specific cluster sizes for which an additional excitation level calculated by diffusion Monte Carlo is stabilized. The present theoretical study provides an alternative explanation based on a simple independent particle model of the He clusters. Collisions between cluster atoms in excited states within the cluster lead to selective evaporation via an Auger process. The calculated magic numbers as well as the shape of the number distributions are in quite reasonable agreement with the experiments. |
| Keywords: | Van der Waals bonds helium clusters Auger evaporation magic numbers cluster supersonic jets |