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Tornow, Sabine, Bulla, Ralf, Anders, Frithjof B. and Zwicknagl, Gertrud (2010). Multiple-charge transfer and trapping in DNA dimers. Phys. Rev. B, 82 (19). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

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Abstract

We investigate the charge transfer characteristics of one and two excess charges in a DNA base-pair dimer using a model Hamiltonian approach. The electron part comprises diagonal and off-diagonal Coulomb matrix elements such a correlated hopping and the bond-bond interaction, which were recently calculated by Starikov [E. B. Starikov, Philos. Mag. Lett. 83, 699 (2003)] for different DNA dimers. The electronic degrees of freedom are coupled to an ohmic or a superohmic bath serving as dissipative environment. We employ the numerical renormalization group method in the nuclear tunneling regime and compare the results to Marcus theory for the thermal activation regime. For realistic parameters, the rate that at least one charge is transferred from the donor to the acceptor in the subspace of two excess electrons significantly exceeds the rate in the single charge sector. Moreover, the dynamics is strongly influenced by the Coulomb matrix elements. We find sequential and pair transfer as well as a regime where both charges remain self-trapped. The transfer rate reaches its maximum when the difference of the on-site and intersite Coulomb matrix element is equal to the reorganization energy which is the case in a guanine/cytosine (GC)-dimer. Charge transfer is completely suppressed for two excess electrons in adenine/thymine (AT)-dimer in an ohmic bath and replaced by damped coherent electron-pair oscillations in a superohmic bath. A finite bond-bond interaction W alters the transfer rate: it increases as function of W when the effective Coulomb repulsion exceeds the reorganization energy (inverted regime) and decreases for smaller Coulomb repulsion.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Tornow, Sabine UNSPECIFIED UNSPECIFIED UNSPECIFIED Bulla, Ralf UNSPECIFIED UNSPECIFIED UNSPECIFIED Anders, Frithjof B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zwicknagl, Gertrud UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-492616
DOI:	10.1103/PhysRevB.82.195106
Journal or Publication Title:	Phys. Rev. B
Volume:	82
Number:	19
Date:	2010
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9969
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ELECTRON-TRANSFER; CONDUCTANCE; OXIDATION; DYNAMICS; MODEL Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/49261