Erlangen 2018 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 23: Resonant Energy Transfer and Interatomic Coulombic Decay II
MO 23.4: Vortrag
Freitag, 9. März 2018, 11:15–11:30, PA 1.150
Ultrafast intermolecular relaxation process in hydrated biomolecule cluster — •Xueguang Ren, Enliang Wang, Khokon Hossen, and Alexander Dorn — Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
It is accepted that DNA lesions are induced by secondary species like radicals and the abundant low-energy secondary electrons generated by the primary radiation. In the present work we report the observation of hitherto unrecognized damage mechanism in form of a non-local autoionizing process called intermolecular coulombic decay (ICD) which directly ionizes DNA constituents in an aqueous environment. As a model system hydrogen-bonded dimers are used which consist of one tetrahydrofuran (THF) molecule - a surrogate of deoxyribose in the DNA backbone - and one water molecule. After inner-valence ionization of water by electron impact the vacancy is filled by an electron from an outer-valence orbital and ultrafast energy transfer across the hydrogen bridge leads to ionization of the neighboring THF molecule and ejection of an electron. This energy transfer from water to THF is faster than the otherwise occurring intermolecular proton transfer. The signature of the ICD reaction is identified in triple coincidence measurements of both ions and one of the final state electrons.