Electron ionization of N2O

Abstract

Relative partial ionization cross sections and precursor specific partial ionization cross sections for electron ionization of N₂O have been determined using time-of-flight mass spectrometry and ion–ion coincidence techniques. Cross sections are reported for ionizing energies from 30–200 eV. Data are presented for the formation of N²⁺, O²⁺, N⁺, O⁺, N₂O²⁺, N₂⁺ and NO⁺ relative to N₂O⁺. Good agreement is found between our data and one set of recently published absolute partial ionization cross sections. However, some discrepancies are observed between the results presented here and two earlier determinations of the absolute partial ionization cross sections. We ascribe these discrepancies to incomplete collection of translationally energetic fragment ions in the earlier studies, providing additional evidence for the incomplete collection of translationally energetic product ions in some determinations of partial ionization cross sections. Our precursor specific cross sections allow the contribution from single, double and triple ionization to the individual fragment ion yields, following ionization of N₂O, to be quantified for the first time.