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MO: Molekülphysik

MO 17: Poster II

MO 17.19: Poster

Donnerstag, 25. März 2004, 14:00–16:00, Schellingstr. 3

Photoelectron Spectroscopy of Isolated Multiply Charged Oligonucleotides — •J. Mathias Weber¹, Ilya N. Ioffe², Katja M. Berndt¹, Daniel Löffler¹, Jochen Friedrich¹, Oli T. Ehrler¹, Joel H. Parks³, and Manfred M. Kappes¹ — ¹Institut für Physikalische Chemie, Universität Karlsruhe, D-76128 Karlsruhe, Germany — ²Chemistry Department, Moscow State University, Moscow 119899, Russia — ³The Rowland Institute at Harvard, 100 Edwin H. Land Boulevard, Cambridge, MA 02142, USA

Mass spectrometry and ultraviolet photoelectron spectroscopy were used to investigate the electronic properties of isolated DNA oligonucleotides. [dA₅ − 4H]⁴⁻, and [dT₅ − 4H]⁴⁻ ions carrying four negative charges were formed by electrospray ionization and mass selected in an ion beam. Their photoelectron spectra were analyzed using a magnetic bottle electron spectrometer. We find the fourth electron affinity to be slightly negative (-0.30(15) eV) for [dA₅ − 4H], while it is positive (+0.90(15) eV) for [dT₅ − 4H]. This significant influence of the base composition on energetics is in turn relevant for analytic applications as well as in the context of DNA charge transfer properties.