Estimate of the Reorganization Energy for Charge Transfer in DNA

The solvent reorganization energy λs can have a significant effect on the activation energy for charge transfer in DNA and its dependence on donor (D)−acceptor (A) distance R DA. To estimate λs and the resulting effective contribution β s to the falloff parameter β for the overall transfer rate cons...

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Bibliographic Details
Published in:The journal of physical chemistry. B 2003-03, Vol.107 (11), p.2595-2601
Main Authors: Siriwong, Khatcharin, Voityuk, Alexander A, Newton, Marshall D, Rösch, Notker
Format: Article
Language:English
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Summary:The solvent reorganization energy λs can have a significant effect on the activation energy for charge transfer in DNA and its dependence on donor (D)−acceptor (A) distance R DA. To estimate λs and the resulting effective contribution β s to the falloff parameter β for the overall transfer rate constant, the Poisson equation was solved numerically for several systems representing DNA duplexes, 5‘-GGGT n GGG-3‘, in a realistically structured heterogeneous dielectric, as determined by molecular dynamics (MD) simulations. The charge transfer was modeled primarily for holes localized on single guanine bases. Effects of thermal fluctuations on λs were taken into account via structures for a given duplex sampled from MD trajectories. Calculated values of λs were found to be rather insensitive to thermal fluctuations of the DNA fragments but depended in crucial fashion on details of the dielectric model (shape and dielectric constants of various zones) that was used to describe the polarization response of the DNA and its environment to the charge transfer. λs was calculated to increase rapidly at small R DA values (
ISSN:1520-6106
1520-5207
DOI:10.1021/jp027052q