Mass spectrometric investigation of dissociative ionization of toxic gases by electrons at 20-1000 eV.

Measurements of the dissociative ionization cross-sections of CO, CO2, NO and N2O molecules for electrons from 20 up to 1000 eV were performed. Total collection of ions was achieved by using a specially constructed cycloidal mass spectrometer, an ion source without slit and a collector with large area. In that open ion source the effusion molecular beam formed by a capillary was crossed by the electron beam. Owing to such parameters of the mass spectrometer the mass discrimination effects were reduced. At the ionization of CO molecules, the ions CO+, C+, O+ and CO2+ were registered; at CO2, the ions CO2+, CO+, O+, C+ and CO2(2)+; at NO, the ions NO+, N+, O+ and NO2+; at N2O, the ions N2O+, NO+, N2+, O+, (N+,N2(2)+) and N2O2+. The relative values of the partial cross-sections were normalized to the absolute total ionization cross-sections obtained by Rapp and Englander-Golden.