Ionization and fragmentation of furan molecules by electron collisions

Cation mass spectra obtained by electron impact were measured to investigate the ionization and ionic fragmentation of furan, C4H4O, molecules in the gas phase. The most abundant cations, with comparable intensities in the mass spectra, were the parent, C4H4O+, cation (68 amu) and the C3H3+ fragment (39 amu). The appearance energies of most of the observed ionic fragments were determined and the possible fragmentation processes are discussed. The electron-impact absolute total and partial ionization cross sections in furan were measured using the total ion collection technique over the energy range from the respective ionization thresholds to 150 eV.