When ionizing radiation passes biological matter, a large number of secondary electrons with very low energies (<3 eV) is produced. It is known that such electrons cause an efficient fragmentation of isolated nucleobases via dissociative electron attachment. We present an experimental study of the electron attachment to microhydrated nucleobases. Our novel approach allows significant control over the hydration of molecules studied in the molecular beam. We directly show for the first time that the presence of a few water molecules suppresses the dissociative channel and leads exclusively to formation of intact molecular and hydrated anions. The suppression of fragmentation is ascribed to caging-like effects and fast energy transfer to the solvent. This is in contrast with theoretical prediction that microhydration strongly enhances the fragmentation of nucleobases. The current observation impacts mechanisms of reductive DNA strand breaks proposed to date on the basis of gas-phase experiments.

J Heyrovský Institute of Physical Chemistry v v i The Czech Academy of Sciences Dolejškova 3 18223 Prague Czech Republic

Citace poskytuje Crossref.org

Condensed Matter Systems Exposed to Radiation: Multiscale Theory, Simulations, and Experiment

Stabilization of benzene radical anion in ammonia clusters

Low-Energy Electron Induced Reactions in Metronidazole at Different Solvation Conditions

5-Nitro-2,4-Dichloropyrimidine as an Universal Model for Low-Energy Electron Processes Relevant for Radiosensitization

Ring Formation and Hydration Effects in Electron Attachment to Misonidazole

Low-energy electrons transform the nimorazole molecule into a radiosensitiser

Suppression of low-energy dissociative electron attachment in Fe(CO)5 upon clustering