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권오훈

Kwon, Oh Hoon
Ultrafast Laser Spectroscopy and Nano-microscopy Lab.
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Double proton transfer dynamics of model DNA base pairs in the condensed phase

Author(s)
Kwon, Oh HoonZewail, Ahmed H.
Issued Date
2007-05
DOI
10.1073/pnas.0702944104
URI
https://scholarworks.unist.ac.kr/handle/201301/8767
Fulltext
http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=34547492394
Citation
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, v.104, no.21, pp.8703 - 8708
Abstract
The dynamics of excited-state double proton transfer of model DNA base pairs, 7-azaindole dimers, is reported using femtosecond fluorescence spectroscopy. To elucidate the nature of the transfer in the condensed phase, here we examine variation of solvent polarity and viscosity, solute concentration, and isotopic fractionation. The rate of proton transfer is found to be significantly dependent on polarity and on the isotopic composition in the pair. Consistent with a stepwise mechanism, the results support the presence of an ionic intermediate species which forms on the femtosecond time scale and decays to the final tautomeric form on the picosecond time scale. We discuss the results in relation to the molecular motions involved and comment on recent claims of concerted transfer in the condensed phase. The nonconcerted mechanism is in agreement with previous isolated-molecule femtosecond dynamics and is also consistent with the most-recent high-level theoretical study on the same pair.
Publisher
NATL ACAD SCIENCES
ISSN
0027-8424
Keyword (Author)
7-azaindolefemtochemistryreaction dynamicstautomerization
Keyword
HYDROGEN-BONDED COMPLEXES7-AZAINDOLE DIMEREXCITED-STATEFEMTOSECOND DYNAMICSMOLECULAR-DYNAMICSGAS-PHASEISOTOPENMRTAUTOMERISMCONTROVERSY

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