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Proceedings Paper

Dynamics Of Solvated Electron Formation From Dna Irradiated By Intense Laser Pulses
Author(s): Paul A. Cornelius; Daniel K. Negus
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Paper Abstract

Solvated electrons are formed in high yield and can be detected by transient absorption spectroscopy when calf thymus DNA is irradiated with laser pulses at 266 nm having peak intensities above 1014 W/m2. Approximately 20% of the initially appearing absorption strength decays with a time constant of 400 ps, while the remaining 80% is long-lived (> 10 ns). The decaying component may indicate geminate recombination of the photoejected electron. Spectral evidence suggests that the bases are the site of ionization. The signal is observed to depend nonlinearly on the excitation pulse energy, indicating that two (or more) excitation quanta at 266 nm are required to ionize DNA. An equimolar mixture of nucleosides shows a much lower quantum yield for electron formation; this is discussed in terms of an exciplex model for the DNA excited state.

Paper Details

Date Published: 10 March 1987
PDF: 9 pages
Proc. SPIE 0712, Lasers in Medicine, (10 March 1987); doi: 10.1117/12.937330
Show Author Affiliations
Paul A. Cornelius, Molecular Biophysics Technology, Inc. (United States)
Daniel K. Negus, Molecular Biophysics Technology, Inc. (United States)

Published in SPIE Proceedings Vol. 0712:
Lasers in Medicine
Stephen N. Joffe M.D.; John A. Parrish M.D., Editor(s)

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