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MO: Molekülphysik

MO 8: Energietransfer, Reaktionen

MO 8.4: Talk

Wednesday, March 6, 2002, 14:45–15:00, HS 01/E01

Ion induced excitation and fragmentation of an RNA base — •Jur de Vries, Ronnie Hoekstra, Reinhard Morgenstern, and Thomas Schlathölter — KVI Atomic Physics, Zernikelaan 25, 9747AA Groningen, The Netherlands

Energy deposition into biomolecules and the subsequent de-excitation pathways belong to the most fundamental processes occurring in living organisms. The different de-excitation pathways can be investigated e.g. by mass spectrometry, where they in turn lead to characteristic fragmentation patterns. Multiply charged ions (MCI) might be an interesting tool to excite biomolecules in a controlled way and gain information on fragmentation dynamics and molecular structure not accesible by the established mass-spectrometric methods. Radiation damage in biological tissues is to a large extent induced by secondary processes such as interaction of cellular DNA with hyperthermal electrons as well as ions containing inner-shell vacancies. To investigate the latter, we study the interaction of slow MCI with the RNA base uracil. In our coincidence time-of-flight (TOF) experiment a reflectron-type mass spectrometer is employed to investigate the influence of the parameters ion charge q, velocity v and atomic number Z on the fragmentation spectra. Experiments are performed e.g. with a chopped beam to measure the statistical distribution of the fragments or using a continuous beam to detect fragment ions in coincidence with emitted electrons or other fragments from the same event. This way, we can investigate particular de-excitation channels and even deduce the kinetic energy release. The results are compared to data obtained by other fragmentation techniques.