Hannover 2013 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 8: Spectroscopy in He-Droplets

MO 8.4: Vortrag

Montag, 18. März 2013, 17:15–17:30, F 107

Catching biomolecular ions with liquid helium nanodroplets — •Ana Isabel Gonzalez Florez, Doo-Sik Ahn, Frank Filsinger, Gerard Meijer, and Gert von Helden — Fritz-Haber-Institut der MPG, Berlin, Germany

Liquid helium nanodroplets are an ideal matrix for the spectroscopic study of molecules. The droplets are isothermal at 0.38 K, superfluid, weakly interacting with the embedded molecule, and transparent over a wide spectral range [1]. We have built up an experimental setup [2, 3] that allows the doping of selected ions in helium droplets. In our experiment, biological molecules are brought into the gas phase via electrospray ionization. They are then mass-to-charge selected using a quadrupole mass spectrometer, and stored in a linear ion trap where they are picked up by helium droplets. Further downstream, the charged droplets are investigated and detected.

In this talk, we will present the electronic spectra of protonated tryptophan and of protonated tryptamine in liquid helium droplets. We will show that the broad electronic spectra of these protonated molecules becomes narrower and blue-shifted by hydration with one water molecule, or by adding the crown ether 18-crown-6. Currently, we are working with larger peptides. An update of those systems will be discussed as well.

[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)

[3] F. Filsinger et al., PCCP, 1-8 (2012)