Stuttgart 2012 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 6: Femtosecond Spectroscopy I

MO 6.1: Vortrag

Montag, 12. März 2012, 16:30–16:45, V38.03

CRASY: Correlated Rotational Alignment Spectroscopy with 70 MHz resolution — •Christian Schröter and Thomas Schultz — Max-Born-Institut, Berlin

Our aim is the investigation of photochemical reactions in biological chromophores, such as DNA-bases. Biological chromophores can occur in different structural conformations, and the assignment of spectroscopic data to a specific molecular structure is difficult. With CRASY, we are able to measure correlated data to characterize nuclear and electronic structure simultaneously (1). CRASY is a method which combines rotational spectroscopy in the time domain with femtosecond-pump-probe experiments. An IR pulse generates a coherent rotational wave packet by means of non-adiabatic alignment. After a variable delay, we probe the wave packet by a UV pulse which excites and ionizes the molecule via a resonant electronic state. A Fourier transform of collected electron and ion signals reveals the rotational Raman spectrum for each species in the sample. For the reliable assignment of biomolecular isomers, we require a good rotational resolution. Here we present CRASY measurements with a resolution below 70 MHz, sufficient for the characterization of DNA-base tautomers.

(1) Science 333, 1011 (2011)