Hamburg 2009 – scientific programme
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MO: Fachverband Molekülphysik
MO 11: Kalte Moleküle 2
MO 11.7: Talk
Tuesday, March 3, 2009, 15:30–15:45, VMP 6 HS-G
Measurement of small photodestruction rates of cold, charged biomolecules in an ion trap — •David Offenberg, Christian Wellers, Chaobo Zhang, Bernhard Roth, and Stephan Schiller — Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
Photodestruction spectroscopy is a common tool to gain information on structures of biomolecules or to study the energetics and pathways of fragmentations. The investigation of these processes on cooled molecular ions in ion traps provides advantageous conditions. Through the long storage times here, the time scale of observable destruction processes can be extended to rates smaller than 1 s−1 that are not accessible with non-trapping approaches. In future, by internal cooling the trapped molecules, spectral congestion and inhomogeneous line broadening can be reduced and photodestruction spectra of high resolution can be obtained. We have demonstrated two techniques for the measurement of photodestruction rates on singly protonated molecules of the organic compound glycyrrhetinic acid (C30H46O4) in a linear ion trap, dissociated by a continuous-wave UV laser (266 nm) at different intensities [1]. The molecules were sympathetically cooled by simultaneously trapped laser-cooled barium ions to translational temperatures < 150 mK. Destruction rates of less than 0.05 s−1 and a cross section of (1.1±0.1)·10−17 cm2 have been determined. An extension to tunable UV laser sources would permit high-resolution dissociation spectroscopic studies on a wide variety of cold complex molecules.
[1] D. Offenberg et al., to appear in J. Phys. B, arXiv:0810.5097v2