1. Institute of Theoretical Chemistry and Radiation Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria, Institute of Physics, N. Copernicus University, Grudziadzka 5, 87-100 Toruń, Poland, Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstrasse 12, 53115 Bonn, Germany, and Austrian Society for Aerospace MedicineInstitute for Space Biophysics, Lustkandlgasse 52, 1090 Vienna, Austria