Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 36: TR: Poster Session

TT 36.15: Poster

Donnerstag, 25. März 2010, 14:00–18:00, Poster A

Multiple-charge transfer and trapping in DNA dimers — •Sabine Tornow¹, Ralf Bulla², Frithjof Anders³, and Gertrud Zwicknagl¹ — ¹Institut fuer Mathematische Physik, TU Braunschweig, 38106 Braunschweig, Germany — ²Institut fuer Theoretische Physik, Universitaet zu Koeln, 50937 Koeln, Germany — ³Theoretische Physik II, TU Dortmund, 44221 Dortmund, Germany

We investigate the transfer characteristics of multiple charges in a DNA base-pair dimer using a model Hamiltonian approach. It comprises different Coulomb matrix elements which where calculated recently by Starikov [E. B. Starikov, Phil. Mag. Lett. 83, 699 (2003)] as well as the dissipative environment which is modeled by a bosonic bath. In the nuclear tunneling regime we employ the Numerical Renormalization Group method whereas in the thermal activation regime a scheme of kinetic equations and Marcus rates is used to calculate the time-dependent population probabilities. We find that the mobility of two excess charges depends strongly on the Coulomb-matrix elements which differ for the different base pairs. Starting with two electrons on the donor, the Coulomb matrix elements determine, if, e.g, both electrons are self-trapped, transferred as a pair or only one of the electrons is transferred. The latter can be even activation-less when the difference of the on-site and inter-site Coulomb matrix element is equal to the reorganization energy which is the case in a GC-GC dimer. Whereas two excess electrons in AT-AT, dependent on the temperature and spectral function of the environment, are either self-trapped or are oscillating as a pair.