Electron impact ionization and cationic fragmentation of the pyridazine molecules

Electron impact mass spectroscopy was used to investigate ionization and cationic fragmentation of the pyridazine (1,2 diazine), C4 H4 N2 , molecules in the gas phase. The mass spectra were measured and the observed mass peaks assigned to the corresponding cations. The appearance energies of most of the cationic fragments were determined and the possible fragmentation processes are discussed. The total cross section for electron impact ionization of pyridazine was calculated using the binary-encounter-Bethe (BEB) model. The calculated cross section was applied to normalize the measured cation yield curves and total and partial cross sections for ionization and cationic fragmentation were obtained over the energy range from the respective ionization thresholds to 140 eV.