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Author King, Sarah B. ♦ Yandell, Margaret A. ♦ Kunin, Alice ♦ Stephansen, Anne B. ♦ Yokoi, Yuki ♦ Takayanagi, Toshiyuki ♦ Neumark, Daniel M.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ ANIONS ♦ BOUND STATE ♦ DIPOLES ♦ DNA ♦ ELECTRON ATTACHMENT ♦ ELECTRONS ♦ EV RANGE ♦ EXCITATION ♦ IODIDES ♦ IODINE ♦ MEV RANGE ♦ PULSES ♦ THYMINE ♦ TIME RESOLUTION
Abstract The dynamics of electron attachment to the DNA base thymine are investigated using femtosecond time-resolved photoelectron imaging of the gas phase iodide-thymine (I{sup −}T) complex. An ultraviolet pump pulse ejects an electron from the iodide and prepares an iodine-thymine temporary negative ion that is photodetached with a near-IR probe pulse. The resulting photoelectrons are analyzed with velocity-map imaging. At excitation energies ranging from −120 meV to +90 meV with respect to the vertical detachment energy (VDE) of 4.05 eV for I{sup −}T, both the dipole-bound and valence-bound negative ions of thymine are observed. A slightly longer rise time for the valence-bound state than the dipole-bound state suggests that some of the dipole-bound anions convert to valence-bound species. No evidence is seen for a dipole-bound anion of thymine at higher excitation energies, in the range of 0.6 eV above the I{sup −}T VDE, which suggests that if the dipole-bound anion acts as a “doorway” to the valence-bound anion, it only does so at excitation energies near the VDE of the complex.
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-07-14
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 143
Issue Number 2


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