Berlin 2005 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 30: POSTER: Chemical physics

CPP 30.57: Poster

Dienstag, 8. März 2005, 16:30–18:30, Poster TU D

Nonlinear Dynamics of Vibrational Excitons in Polypeptides — •Dmitry Tsivlin and Volkhard May — Institut für Physik, Humboldt Universität zu Berlin, Newtonstraße 15, D-12489 Berlin, Germany

Ultrafast infrared spectroscopy of polypeptides and small proteins attracted a lot of interest in recent years. Concentrating on high-frequency vibrations of the peptide unit, such as amide I modes, delocalization and relaxation could be observed mainly in the framework of multidimensional spectroscopy. In Ref. [1] the observation of a self–trapped vibrational state in the helical conformation of poly–γ–benzyl–L–glutamate has been reported using recent studies on two–vibron bound states [2]. By introducing the concept of adiabatic excitons we reexamine these states of the helix. Diagonalizing the full Hamiltonians responsible for the presence of a different number of peptide group excitations we can study various mechanisms leading to the self–trapping of, e.g. the amide I or N–H mode. Relaxation channels for their deexcitation are also discussed. Some preliminary results on a mixed quantum–classical description of the formation and decay of self–trapped states are reported.

[1] J. Edler, et al., Phys. Rev. Lett. 93, 106405 (2004)

[2] V. Pouthier, Phys. Rev. E 68, 021909 (2003)