Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 7: Clusters II: Non-Metal Clusters, Fullerenes, Nanotubes (joint session A and MO)

A 7.2: Vortrag

Dienstag, 3. April 2001, 16:00–16:15, H1012

Fluorescence Spectroscopy of Doped Rare Gas Clusters with a Shell-Like Structure — •Tim Laarmann, Klaus von Haeften, Hubertus Wabnitz, and Thomas Möller — HASYLAB am DESY, Notkestr. 85, 22607 Hamburg, Germany

In this contribution, we report on the electronic structure, energy dissipation and transport phenomena in Ar clusters covered with a shell of Kr atoms and embedded in large Ne clusters. The ArKrNe-complex is prepared using a stepwise pick-up technique. After excitation with synchrotron radiation, the emitted fluorescence light was detected by two photomultipliers (sensitivity: 2-6 and 4-11eV). For spectrally resolved measurements in the visible and near-infrared spectral range a monochromator and a CCD camera was used. In the energy range of the Ar-cluster absorption the intensity ratios of bands differ considerably from those of free clusters, due to the influence of the shell atoms. The surface states disappeared and new luminescence bands occur. After excitation of the Ne 1l’-exciton without Kr-doping the fluorescence spectrum consists of sharp lines, due to free atomic Ar transitions (4p-4s). Electronically excited Ar atoms move through the Ne-cluster, desorb and emit in the vacuum. Increasing the Kr pressure, the Ar lines disappear and 5p-5s transitions of Kr become dominant. Additionally, new bands occur, which we interpret as Ar transitions of perturbed atomic 4p-states inside Ne-clusters.