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MO: Fachverband Molekülphysik

MO 1: Biomolecules

MO 1.3: Talk

Monday, March 14, 2011, 11:00–11:15, TOE 317

Catching Proteins in Liquid Helium Droplets — •Frank Filsinger, Frauke Bierau, Peter Kupser, Gerard Meijer, and Gert von Helden — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany

Superfluid helium droplets provide an isothermal ultracold environment for embedded molecules and are ideal matrices for optical spectroscopy [1]. Recently, we set up a new experiment to dope He droplets with biomolecular ions [2]. In this approach, biomolecules are brought into the gas phase via electrospray ionization (ESI) and are selected according to their mass-to-charge ratio in a quadrupole mass spectrometer. The ions are then stored in a linear ion trap, from which they are picked up by a pulsed beam of helium droplets. While in the initial experiments very large He droplets (composed of 10¹⁰-10¹² atoms) were observed [2], a new He droplet source enables us now to embed amino acids, peptides, and even small proteins in droplets consisting of 10⁴ to 10⁶ He atoms depending on the dopant molecules. We will discuss how the size of the doped droplets can be directly measured by accelerating the doped droplets in an electric field. Furthermore, we will present our progress towards IR spectroscopy of these cold biomolecular ions.

[1] J. P. Toennies, A. F. Vilesov, Angew. Chem. Int. Ed. 43, 2622 (2004) [2] F. Bierau et al., Phys. Rev. Lett. 105, 133402 (2010)