Absolute electron impact ionization cross section from threshold up to 180 eV for N2O+e→N2O++2e and the metastable and collision induced dissociation of N2O+

Abstract

Electron impact ionization of nitrous oxide was studied as a function of electron energy up to 180 eV. A double focusing mass spectrometer in combination with an improved electron impact ion source (Stephan et al.) was used, alleviating the problems of ion extraction from the source and the transmission of the extracted ions through the mass spectrometer system. Relative partial ionization cross sections were measured for the process N₂O+e→N₂O⁺+2e. These cross sections were calibrated absolutely by normalizing the relative cross sections with two different methods. A difference obtained in the absolute cross section values is explained by the delayed unimolecular dissociation process N₂O⁺ to NO⁺+N. Both metastable and collision induced dissociation of N₂O⁺ were studied quantitatively using the well established technique of decoupling the acceleration and deflection electric fields.