Düsseldorf 2007 – scientific programme

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MO: Fachverband Molekülphysik

MO 56: Poster: Femtosecond Spectroscopy

MO 56.14: Poster

Thursday, March 22, 2007, 16:30–18:30, Poster A

Analysis and Control of Metal Cluster Reactions by Modulated Ultra-broadband Laser Pulses — •Bruno Schmidt, Shaohui Li, Xin Zhang, Aldo Mirabal, Waldemar Unrau, Juri Demuth, Torsten Siebert, and Ludger Wöste — Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin

The aim of the presented work lies in further developing femtosecond time-resolved NeNePo (negative, neutral, positive) spectroscopy within the study of catalytic reaction properties of noble metal cluster-adsorbate complexes. We seek to expand from the original analysis of the cluster dynamics to an active steering of a reactive system along a desired coordinate through coherent control strategies. To realize this goal, ultra-broadband laser pulses are generated by means of self phase modulation through filamentation in noble gas atmosphere. Subsequently, the obtained pulses can be modulated by a liquid crystal mask within a pulse shaper setup especially designed for manipulating broadband spectra. Within these efforts, emphasis is made on characterizing the spectral phase and amplitude of the broadband, tailored pulses. This instrumentation allows for optimizing a desired reaction pathway in an active feedback loop employing genetic algorithms that control the structure of the excitation pulse. First results on the spectral properties of the continuum generation and capability of four-wave-mixing for analyzing the pulse structure will be presented.