Ionization And Fragmentation Of Pyrimidine And Pyridazine Induced By Proton And Electron Impact

The ionization and fragmentation of pyrimidine and pyridazine have been studied experimentally, by recording the time of flight mass spectra, and theoretically, by calculating the valence shell MOs ionization cross sections. The absolute total non-dissociative and dissociative cross section has been measured between 70 to 400 eV for electron impact on pyrimidine and from 250 to 2500 keV for proton impact on both molecules. The partial yields and the absolute cross sections measured as a function of the energy combined with the model calculation allows us to suggest the vacancy population of the valence MOs from which several sets of fragment ions are produced.