Molecular beam electron spin resonance to study the magnetic behaviour of super-atomic metal clusters

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The central idea of this project is to set up a Rabi experiment for measuring the electron spin resonance of isolated clusters in molecular beams in order to determine the magnetic moments of metal clusters with not yet reached accuracy. Typical experimental techniques for isolated clusters show systematic and statistical errors rarely less than 1 %. In contrast, the Rabi frequencies allow the determination of magnetic moments with an experimental accuracy in the ppm range, i.e. more than two orders of magnitudes better than common methods.Rabi experiments on clusters of heavier metal atoms have not been performed hitherto, since couplings of spin and rotational degrees of freedom usually prevent the preparation of a cluster in a defined spin state. The discovery of endohedrally doped metal clusters exhibiting atom-like magnetic properties has changed these preconditions and Rabi experiments on these type of clusters become available in principle. High precision magnetic moments are a very sensitive probe for their electronic structure, i.e. the chemical bonding between the host cluster cage and the paramagnetic guest atom. Further, these experiments allow the investigation of hyperfine interactions free of interfering solvent or matrix effects.