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Published November 9, 2001 | public
Journal Article

DNA/RNA nucleotides and nucleosides: direct measurement of excited-state lifetimes by femtosecond fluorescence up-conversion


Fluorescence decay times of the nucleosides: adenosine, guanosine, cytidine and thymidine, and of the corresponding nucleotides, were determined using the technique of fluorescence up-conversion with femtosecond time resolution. The excited-state lifetimes of these nucleic acid molecules all fall in the sub-picosecond time scale, confirming the presence of an ultrafast internal conversion channel for both the nucleotides and the nucleosides; the nucleotides lifetimes are longer than those of the nucleosides by up to 20%. The ultrafast internal conversion is biologically relevant to the stability of DNA, and our results support the sub-picosecond repopulation of the ground state, consistent with transient absorption studies on the femtosecond time scale.

Additional Information

© 2001 Elsevier B.V. Received 20 August 2001, Available online 17 October 2001. This work was supported by a grant from the National Science Foundation. We wish to thank Dr. Dongping Zhong for his help with the initial setup of the experiments.

Additional details

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October 20, 2023