Getting to guanine: Mechanism and dynamics of charge separation and charge recombination in DNA revisited

Frederick D. Lewis, Huihe Zhu, Pierre Daublain, Karsten Sigmund, Torsten Fiebig, Milen Raytchev, Qiang Wang, Vladimir Shafirovich

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

The mechanism and dynamics of charge separation and charge recombination in synthetic DNA hairpins possessing a stilbenedicarboxamide linker and a single guanine-cytosine base pair have been reinvestigated. The combination of femtosecond broad-band pump probe spectroscopy, nanosecond transient absorption experiments, and picosecond fluorescence decay measurements permits analysis of the formation and decay of the stilbene anion radical. Reversible hole injection resulting in the formation of the stilbene-adenine contact radical ion pair is found to occur on the picosecond time scale. The mechanism for charge separation across two or more base pairs is revised from single step superexchange to a multi-step process: hole injection followed by hole transport and hole trapping. The mechanism of charge recombination remains assigned to a superexchange process.

Original languageEnglish (US)
Pages (from-to)534-539
Number of pages6
JournalPhotochemical and Photobiological Sciences
Volume7
Issue number5
DOIs
StatePublished - May 19 2008

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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