Heidelberg 2015 – scientific programme

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MO: Fachverband Molekülphysik

MO 15: Clusters in Molecular Physics (with A & MS)

MO 15.5: Talk

Wednesday, March 25, 2015, 15:45–16:00, PH/SR106

Optical spectra and structures of C, N, and O-doped silicon clusters — •Bertram K.A. Jaeger, Janina Lebendig, Nguyen X. Truong, Andre Fielicke, and Otto Dopfer — IOAP, TU Berlin, Germany

Controlled changes in physical and chemical properties of doped Si clusters provide promising candidates of nanostructures for optoelectronics, sensors or medicine. We study Si clusters doped with C, N and O via their photodissociation spectra and compare them with theoretical quantum chemical calculations. Ionic clusters are produced in a laser vaporization source, then irradiated with tunable visible light from an OPO laser in the range from 410 to 580 nm and characterized by a reflectron time-of-flight mass spectrometer. Absorption of photons leads to dissociation of the clusters, which is detected in the mass spectrum. Calculated absorption spectra are compared to experimental data for assignment of geometries and electronic parameters of the observed clusters. The most stable and low-energy isomers are found with the help of genetic and basin-hopping algorithms. All results will be compared to existing studies about IR-UV two color ionization of neutral and doped Si clusters.

Pristine and tagged Au clusters show absorption bands in the visible range and are used as a test system to verify the experimental principle.