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MO: Molekülphysik
MO 29: Poster: Biomolecules
MO 29.1: Poster
Tuesday, March 14, 2006, 16:30–18:30, Labsaal
Site selectivity in dissociative free-electron attachment to gas phase nucleobases — •Sylwia Ptasinska1, Stephan Denifl1, Fabio Zappa1,2, Verena Grill1, Paul Scheier1, and Tilmann D. Märk1 — 1Institut für Ionenphysik, Leopold-Franzens Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria — 2UNESA, Rio de Janeiro, Brasil
The interaction of low energy electrons with DNA has been demonstrated to be an important mechanism in the production of both single and double strand breaks, even at sub-ionization energies [1]. Furthermore, the yield of such DNA damage shows a resonant behaviour with energy which is an indication of transient negative ion formation. In this contribution we will show the results of a series of gas phase experiments concerning free-electron attachment to the nucleobases thymine and uracil and partially deuterated or methylated derivatives. By careful analysis of the experimental data, we are able to assign each of the resonances of the abundant fragment anions (M-H)- and H- observed to the cleavage of an H atom from a specific site in these molecules.
This work was supported by FWF (Wien), the EU commission (Brussels, through the EPIC network and the COST Action P9). F.Z gratefully acknowledges a post-doc grant from the Brazilian agency CNPq.
[1] M. A. Huels, B. Boudaiffa, P. Cloutier, D. Hunting, L. Sanche, J. Am. Chem. Soc. 125(2003) 4467;