Soft X-ray spectroscopy of clusters, surfaces and interfaces

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Sputter source for metallic clusters ·

Sputter source for metallic clusters

We have developed a transportable (and synchrotron compatible), UHV cluster source named ICARUS which enables us to perform core-electron spectroscopy on well-defined, mass-selected, in-situ deposited metal clusters (n < 20; n number of atoms). The clusters are produced in a sputtering process, mass-selected with a magnetic mass spectrometer and finally deposited under soft-landing conditions (in an Ar-matrix) on a single crystal substrate.

"Soft-landing"

Our experiments on Fe, Ni, and Cr-clusters show that we are able to soft-land small clusters on a substrate and investigate them with inner-shell spectroscopies. It has been possible for the first time to spectroscopically identify small deposited clusters using near-edge x-ray absoprtion spectroscopy. For iron-clusters we have been able to show that for fragmentation-free deposition about 10-15 layers of Ar are necessary. Deposition in thinner Ar-layers leads to fragmentation of the smallest clusters upon deposition.