ELECTRON-IMPACT IONIZATION CROSS-SECTIONS OF MOLECULES .1. EXPERIMENTAL-DETERMINATION OF PARTIAL IONIZATION CROSS-SECTIONS OF SF6 - A CASE-STUDY

Electron impact ionization of SF6 has been studied as a function of electron energy from threshold up to 180 eV using a Nier type ion source in combination with a double focusing sector field mass spectrometer (reversed geometry). Absolute partial ionization cross section functions for the production of SF+5, SF+{radical dot}4, SF+3, SF+{radical dot}2, SF+, S+{radical dot}, F+, SF2+4 and SF2+2 have been determined using an improved experimental method based on ion trajectory calculations. In addition, the total ionization cross section function of SF6 has been obtained. The present data are compared with previous experimental and theoretical results in order to evaluate the reliability and accuracy of the method used. © 1990.