Magic Numbers in Boson <sup>4</sup>He Clusters: The Auger Evaporation Mechanism

The absence of magic numbers in bosonic <sup>4</sup>He 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...

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Bibliographic Details
Main Authors: Elena Spreafico, Giorgio Benedek, Oleg Kornilov, Jan Peter Toennies
Format: Article
Language:English
Published: MDPI AG 2021-10-01
Series:Molecules
Subjects:
Online Access:https://www.mdpi.com/1420-3049/26/20/6244
Description
Summary:The absence of magic numbers in bosonic <sup>4</sup>He 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.
ISSN:1420-3049