Heidelberg 2015 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 8: Theory: Quantum Chemistry
MO 8.7: Vortrag
Dienstag, 24. März 2015, 12:45–13:00, PH/HS1
Using ICD for structural analysis of clusters: A case study on NeAr clusters — •Elke Faßhauer1, Marko Förstel2, Sebastian Pallmann3, Markus Pernpointner3, and Uwe Hergenhahn4 — 1CTCC, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway — 2University of Hawai’i at Manoa, 96816 HI Honolulu, USA — 3Theoretische Chemie, Universität Heidelberg, 69120 Heidelberg, Germany — 4Max Planck Institute for Plasma Physics, 17491 Greifswald, Germany
We present a method to utilize Interatomic Coulombic Decay (ICD) to retrieve information about mean geometric structures of heteronuclear clusters. It is based on observation and modelling of competing ICD channels, which involve the same initial vacancy, but energetically different final states with vacancies in different components of the cluster. Using binary rare gas clusters of Ne and Ar as an example, we measure the relative intensity of ICD into (Ne+)2 and Ne+Ar+ final states with spectroscopically well separated ICD peaks. We compare in detail the experimental ratios of the Ne-Ne and Ne-Ar ICD contributions and their positions and widths to values calculated for a diverse set of possible structures. We conclude that NeAr clusters exhibit a core-shell structure with an argon core surrounded by complete neon shells and, possibly, further incomplete shell of neon atoms for the experimental conditions investigated. Our analysis allows to differentiate between clusters of similar size and stochiometric Ar content, but different internal structure. We find evidence for ICD of Ne 2s−1, producing Ar+ vacancies in the second coordination shell of the initial site.