Electron impact ionization of trichlorosilyl, dichlorosilylene, and chlorosilylidyne

Absolute cross sections for the formation of singly charged positive ions produced by electron impact on SiCl3, SiCl2 , and SiCl were measured using the fast-neutral-beam technique. The electron energy range covered was from the threshold to 200 eV. The parent ionization cross sections for all three radicals SiCl3, SiCl 2, and SiCl exhibit similar double-maximum structures which have been observed in other Cl-containing molecules. The largest partial ionization cross sections produced from electron impact on SiCl3 were the SiCl+ and Cl+ fragment ions with maximum values of 3.71A2 and 3.60A2, respectively. The largest partial ionization cross section produced from electron impact on both SiCl2 and SiCl was the Si+ fragment ion with maximum values of 4.80 A2 for SiCl2 and 3.25 A2 for SiCl. The experimentally determined total single ionization cross sections of SiCl3, SiCl2, and SiCl are compared with the results of calculated cross sections using the Deutsch-Mark (DM) formalism.