Electron impact ionization of thymine clusters embedded in superfluid helium droplets F. Zappa, S. Denifl, I. Mähr, J. Lecointre, F. Rondino, Olof Echt, T. D. Märk and P. Scheier Eur. Phys. J. D, 43 1-3 (2007) 117-120 Published online: 24 May 2007 DOI: 10.1140/epjd/e2007-00093-9