Electron impact dissociative ionization and the subsequent ion-molecule reactions in a methane beam Original Research Article

The cross-sections of the electron impact dissociative ionization of methane have been measured for electron energies from threshold to 100 eV. For CH4+ the results agree with the existing measurements. For the fragments of CH3+, CH2+, CH+, and C+, our results overlap with the previous results within their reported error limits. These earlier measurements exceed their given error limits and hence are inconsistent. At higher backing pressures the subsequent ion-molecule reactions and their product ions have been measured.