Analysis of ultrafast relaxation in photoexcited DNA base pairs of adenine and thymine

Citation data:

Chemical Physics, ISSN: 0301-0104, Vol: 347, Issue: 1, Page: 376-382

Publication Year:
2008
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Repository URL:
http://scholarworks.unist.ac.kr/handle/201301/6250
DOI:
10.1016/j.chemphys.2007.09.046
Author(s):
Samoylova, E.; Schultz, Thomas; Hertel, I.V.; Radloff, W.
Publisher(s):
Elsevier BV; ELSEVIER SCIENCE BV
Tags:
Chemistry; Physics and Astronomy; Adenine; DNA photochemistry; Excited state relaxation; Internal conversion; Multiphoton ionization; Thymine; Time-resolved spectroscopy
article description
The photoinduced dynamics in base pairs of adenine and thymine were analyzed by femtosecond pump-probe spectroscopy. On the short-time scale up to a few picoseconds, the characteristic time constants for the dimers are quite similar to the corresponding values of the monomers. This leads to the conclusion that ultrafast intramolecular relaxation proceeds via ππ ∗ and n π ∗ states of one component within the dimer. On the long-time scale, we obtained a novel time constant of roughly 40 ps for the thymine dimer and the adenine–thymine base pair. This time constant was never observed in the monomers and is tentatively assigned to an intermolecular relaxation process, possibly via a hydrogen transfer state.