Hannover 2003 – scientific programme
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MO: Molekülphysik
MO 4: Kleine molekulare Cluster
MO 4.7: Talk
Tuesday, March 25, 2003, 15:30–15:45, B 305
Exciting gas-phase biomolecules — •Joost M. Bakker1, Luke MacAleese1, Gert von Helden1, and Gerard Meijer1,2,3 — 1FOM Institute Rijnhuizen, Edisonbaan 14, NL-3439 MN Nieuwegein — 2University of Nijmegen, Toernooiveld 1, NL-6525 ED Nijmegen — 3Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin
We present gas phase Infrared (IR) spectra of the amino acid Tryptophan. Tryptophan is a highly flexible molecule that is known to exist in many different conformations. The aim of the experiment is to obtain IR spectral information of different, well-defined conformers in order to learn about the structure. This is done by IR excitation, followed by conformer specific UV ionization.
As different conformations can have different excitation energies to the first electronically excited state, IR spectra of specific conformations can be measured. For Tryptophan, the IR spectra are found to be highly dependent on the conformation. The comparison of the experiment with results from quantum-chemical calculations allows for a rather solid structural assignment for the different conformers.