Stuttgart 2012 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 18: Molecular Dynamics

MO 18.1: Hauptvortrag

Donnerstag, 15. März 2012, 14:00–14:30, V38.02

Excited-states and nonadiabatic dynamics: unveiling mechanistic aspects of ultrafast photoprocesses in nucleobases — •Mario Barbatti — Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany

After UV excitation, all five natural nucleobases composing our genetic code return to ground state without photon emission in the time scale of 1 ps. This ultrafast deactivation, which increases the photo-stability of the nucleobases, may have been one of the factors contributing to their selection among a number of other possibilities in early biotic history on Earth. In the last years, theoretical simulations along with time-dependent spectroscopy have worked to determine the excited-state mechanisms employed by these molecules in their ultrafast deactivation. In particular, semi-classical nonadiabatic dynamics simulations have revealed a complex scenario, where multiple different reaction pathways are in constant competition between them [1] and whose output is deeply dependent on details of potential-energy surfaces of each nucleobases [2]. In this contribution, the current state of this topic is reviewed and the strengths and limitations of the available theoretical methods to deal with these phenomema are critically appraised.

[1] M. Barbatti, A. J. A. Aquino, J. J. Szymczak, D. Nachtigallová, P. Hobza, and H. Lischka, Proc. Natl. Acad. Sci. U. S. A. 107, 21453 (2010).

[2] M. Barbatti and S. Ullrich, Phys. Chem. Chem. Phys. 13, 15492 (2011).