Düsseldorf 2007 – scientific programme

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PV: Plenarvorträge

PV II

PV II: Plenary Talk

Tuesday, March 20, 2007, 08:30–09:15, 3A

Electronic and vibrational spectroscopy of cold, gas-phase biological ions — •Thomas Rizzo — Laboratoire de chimie physique moléculaire, Ecole Polytechique Fédérale de Lausanne, CH-1015 Lausanne

The spectroscopic study of small neutral biological molecules in supersonic free jets has provided a wealth of information on their energy landscapes and represents an important means to test the reliability of structure calculations. In such studies, the spectral simplification afforded by the cooling in a supersonic expansion is essential for being able to extract useful information.

Many, if not most, biological molecules exist in the form of closed-shell molecular ions in solution, however, and one would like to have the same degree of spectral simplification for such species as for neutrals. Toward this end, we have constructed a tandem mass spectrometer with a linear 22-pole ion trap that can be cooled down to ∼ 6K. Ions produced by nanospray are mass selected, injected into the trap and cooled through collisions with helium. We then irradiate the cold ions with different combinations of UV and IR laser pulses and measure spectra by detecting fragments that are produced after photon absorption.

In this talk I will present our most recent results on the electronic and vibrational spectroscopy of protonated amino acids, small protonated peptides as well small clusters of these species with a controlled number of solvent molecules. If time permits, I will discuss our preliminary results on multiply-charged oglionucleotides.