Regensburg 2007 – scientific programme

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BP: Fachverband Biologische Physik

BP 8: Charge Transfer

BP 8.5: Talk

Monday, March 26, 2007, 19:00–19:15, H44

Hopping transport through nanowires: a unified approach to DNA charge transfer — Tobias Cramer, Sebastian Krapf, and •Thorsten Koslowski — Institut für Physikalische Chemie, Universität Freiburg, Albertsrasse 23a, D-79104 Freiburg im Breisgau

We address the problem of DNA charge transfer from a theoretical and numerical perspective. The electronic structure is described atomistically and chemically specific by an extended Su-Schrieffer-Heeger Hamiltonian that can be solved self-consistently [1]. The emerging potential energy surface exhibits the characteristics of small polaron formation. It can be analyzed to obtain the parameters relevant to Marcus’ theory of thermally excited charge transfer. The findings are not only compatible with DNA photofragmentation experiments [2], but also provide an accurate description of charge transfer through bio-nano contacts. The resulting rate equations lead to a maximum current of 5 nA per A-DNA double strand upon the application of a potential of ± 2 V, a value comparable to recent experimental findings. In addition, we reproduce the overall shape of the experimental I-V curves and their pronounced dependence upon the DNA sequence [3].

[1] M. Rateitzak, and T. Koslowski, Chem. Phys. Lett. 377, 455 (2003)

[2] T. Cramer, S. Krapf, and T. Koslowski, J. Phys. Chem. B, 108, 11812 (2004); T. Cramer, A. Volta, A. Blumen, and T. Koslowski, J. Phys. Chem. B 108, 16586 (2004)

[3] T. Cramer, S. Krapf, and T. Koslowski, submitted for publication