title: Mass spectrometric investigation of anions formed upon free electron attachment to nucleobase molecules and clusters embedded in superfluid helium droplets.
abstract: Here we report the first mass spectrometric study of negative ions formed via free electron attachment (EA) to nucleobases (NBs) embedded in helium clusters. Pure and mixed clusters of adenine and thymine have been formed by pickup of isolated NB molecules by cold helium droplets. In contrast to EA of isolated molecules in the gas phase we observe a long-lived parent anion NB- and, in addition, parent cluster ions NB-n up to size n=6. Moreover, we show that a low energy electron penetrating into a doped helium droplet causes efficient damage of the embedded nucleobases via resonant, site selective, dissociative electron attachment.
authors.affiliation: Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold Franzens Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
authors.forename: Stephan
authors.initials: S
authors.lastname: Denifl
authors.forename: Fabio
authors.initials: F
authors.lastname: Zappa
authors.forename: Ingo
authors.initials: I
authors.lastname: Mähr
authors.forename: Julien
authors.initials: J
authors.lastname: Lecointre
authors.forename: Michael
authors.initials: M
authors.lastname: Probst
authors.forename: Tilmann D
authors.initials: TD
authors.lastname: Märk
authors.forename: Paul
authors.initials: P
authors.lastname: Scheier