title: Unpaired electron species in thin films of calf-thymus DNA molecules induced by nitrogen and oxygen K-shell photoabsorption.
abstract: The mechanism of DNA modification induced by K-shell photoabsorption of nitrogen and oxygen atoms was investigated by electron paramagnetic resonance and x-ray absorption near edge structure measurements of calf thymus DNA. A g factor of 2.000 for the unpaired electron species, which only arises during irradiation, was measured. The EPR intensities for DNA zwere twofold times larger than those estimated based on the photoabsorption cross section. This suggests that the DNA film itself forms unpaired electron species through the excitation of enhanced electron recapturing, known as the postcollision interaction process.
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan. kotobuki@sanken.osaka-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Oka
authors.forename: A
authors.initials: A
authors.lastname: Yokoya
authors.forename: K
authors.initials: K
authors.lastname: Fujii
authors.forename: Y
authors.initials: Y
authors.lastname: Fukuda
authors.forename: M
authors.initials: M
authors.lastname: Ukai
mesh_terms: D000042:Absorption; D000818:Animals; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004583:Electrons; D009584:Nitrogen / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D055668:Photochemical Processes
chemical_list: D004247:DNA; C427203:calf thymus DNA; D009584:Nitrogen; D010100:Oxygen