Frankfurt 2006 – scientific programme
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MO: Molekülphysik
MO 43: Biomolecules I
MO 43.8: Talk
Wednesday, March 15, 2006, 15:45–16:00, H10
Tautomers and electronic states of jet-cooled 2-aminopurine investigated by double resonance spectroscopy and theory — •Kai Seefeld1, Christian Plützer1, Dennis Löwenich1, Thomas Häber1, Rolf Linder1, Karl Kleinermanns1, Jörg Tatchen2 und Christel Marian2 — 1Institut für Physikalische Chemie I, Heinrich Heine Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf — 2Institut für Theoretische Chemie und Computerchemie, Heinrich Heine Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf
We present resonant two-photon ionization (R2PI), IR-UV, and UV-UV double resonance spectra of jet-cooled 2-aminopurine (2AP) as well as Fourier Transform InfraRed (FTIR) gas phase spectra. 2AP is a fluorescing isomer of the nucleobase adenine. The results show that there is only one tautomer of 2AP which absorbs in the wavelength range 32300-34500 cm−1. The comparison with the calculated IR spectra of 9H- and 7H-2AP points to 9H-2AP as the dominating tautomer in the gas phase but are too similar to allow an unambigous assignment of the experimental spectra to the respective tautomer.
Hence, we determined vertical and adiabatic excitation energies of both tautomers employing combined density functional theory and multi-reference configuration interaction techniques.