Flow injection of liquid samples to a mass spectrometer with ionization under vacuum conditions: a combined ion source for single-photon and electron impact ionization
Cyclobutanone is shown to yield both C3H6+ and C2H2O+ ions on fragmentation under electron impact in a mass spectrometer. Using the energy distribution difference (EDD) technique the ionization energy of cyclobutanone is found to be 9.58 eV and the appearance potentials of the C3H6+ and C2H2O+ ions are found to be 9.85 and 10.53 eV, respectively.
We study the electron-impact induced ionization of O2 from threshold to 120 eV using the electron spectroscopy method. Our approach is simple in concept and embodies the ion source with a collision chamber and a mass spectrometer with a quadruple filter as a selector for the product ions. The combination of these two devices makes it possible to unequivocally collect all energetic fragment ions formed in ionization and dissociative processes and to detect them with known efficiency. The ion source allows varying and tuning the electron-impact ionization energy and the target-gas pressure. We demonstrate that for obtaining reliable results of cross-sections for inelastic processes and determining mechanisms for the formation of O[Formula: see text]([Formula: see text]) ions, it is crucial to control the electron-impact energy for production of ion and the pressure in the ion source. A comparison of our results with other experimental and theoretical data shows good agreement and proves the validity of our approach.
Electron-impact ionization and ionic fragmentation of O2 from threshold to 120 eV energy range