Hannover 2013 – scientific programme
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MO: Fachverband Molekülphysik
MO 14: Poster 1: Cluster, Femtosecond Spectroscopy
MO 14.16: Poster
Tuesday, March 19, 2013, 16:00–18:30, Empore Lichthof
Control of the Photoinduced Dynamics of DCM and Coumarin 307 in the Ultraviolet Regime — •Ina Halfpap, Jürgen Plenge, and Eckart Rühl — Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin
The control of molecular dynamics with femtosecond laser pulses has been intensively studied in recent years and has improved the understanding of molecular photochemical processes [1]. Often, dye molecules have been used as model systems to explore control mechanisms. In particular, the optimization of the two-photon induced fluorescence of different dyes has been investigated using infrared shaped laser pulses [2]. In contrast, the control
of photoprocesses in the linear absorption regime has been far less studied. We present recent results on the control of the relative fluorescence yield following excitation of DCM and Coumarin 307, respectively, in the
linear absorption regime using shaped ultraviolet laser pulses (λ = 400 nm). In one-parameter control experiments a strong influence of the linear chirp on the radiative relaxation of the S1 state has been found. The enhancement
of the relative fluorescence yield with increasing chirp can be explained by a resonance-mediated (1+2) photoionization
process which competes with the radiative relaxation. Complementary results have been obtained from feedback
controlled optimization experiments. The possibility to control the fluorescence yields of dyes can contribute to
an improvement of various techniques, such as fluorescence microscopy.
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