TOTAL AND PARTIAL IONIZATION CROSS-SECTIONS OF NH3 BY ELECTRON-IMPACT

Values of cross sections for the production of positive ions resulting from electron collisions with NH3 at impact energies ranging from threshold to 1 keV have been measured using a crossed-beams apparatus. These cross sections have been normalized by using the relative flow technique and the previously determined cross sections of He and Ne. The measured values are compared with previous data available in the literature. The threshold energy for the production of each ion has been measured. Total ionization cross sections as a function of electron impact energies have been deduced from the measured partial ionization cross sections.