Berlin 2005 – wissenschaftliches Programm
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MO: Molekülphysik
MO 14: Clusters of Atoms and Small Molecules
MO 14.6: Vortrag
Freitag, 4. März 2005, 18:00–18:15, HU 2091
Interatomic Coulombic Decay (ICD) in Heteroclusters of Ne and Ar — •S. Barth, S. Marburger, S. Joshi, V. Ulrich, O. Kugeler, and U. Hergenhahn — Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching
A non-radiative, non-local decay process in weakly bound systems, the Interatomic/molecular Coulombic Decay (ICD) [1], has recently been discovered in Ne clusters [2]. In this decay process, emission of an outer valence electron into the continuum is mediated by an ultrafast energy transfer from a neighbouring atom or molecule, which makes the process very sensitive to the chemical environment of the excited site. This is exemplified by a recent measurement of the lifetime of Ne 2s−1 states in Ne clusters, which yielded 6(1) fs for bulk sites, and more than 30 fs for surface sites [3].
As a step towards an analytical application of ICD, we have investigated the ICD signal of a Ne/Ar mixture coexpanding in a supersonic beam. By changing the nozzle temperature, regimes of pure Ar clusters coexisting with Ne monomers, and of mixed clusters consisting of an Ar core surrounded by Ne layers can be selected. In our experiment we show the appearance of an ICD signal pertaining to a decay of Ne 2s−1 into Ar 3p−1Ne 2p−1 states which is unambiguously related to the formation of a bound system containing Ne and Ar.
[1] L. S. Cederbaum et. al., Phys. Rev. Lett. 79, 4778 (1997).
[2] S. Marburger et. al., Phys. Rev. Lett. 90, 203401 (2003).
[3] G. Öhrwall et. al., Phys. Rev. Lett. 93, 173401 (2004).