Cross sections of the electron impact dissociative ionization of CO, CH4 and C2H2

The cross sections of the electron impact ionization and dissociative ionization of CO, CH4 and C2H2 have been measured for electron energies from threshold to 600 eV. The present values agree with the previous measurements where a complete collection of the resulting ions has been demonstrated experimentally. However, for-the processes where no complete collection has been demonstrated, the present results are usually higher if the ions are produced with higher kinetic energy. The present measurement demonstrates the complete collection of the ions experimentally and the results are thus believed to be reliable. The disagreement between the present results and the previous ones is explained by noting the kinetic energy distributions of the fragment ions.