Processes Induced by Electrons at Sub-Ionization Energies Studied by the Correlated Ions-(Ions/Neutrals) Mass Spectrometry.

Sub-ionization energy electrons play a substantial role in the early time of (radiation/photo-) chemistry by generating reactive ions and neutral radicals. As the ions can be easily identified by mass spectrometry methods, information on the neutral species produced in correlation relies mainly on theoretical calculations. Here we show that coupling a double counter-propagative electron beams with a dual (+/-) time-of-flight mass spectrometer is probably the most versatile instrument for studying processes induced by low energy electrons, by providing correlated information between (ion and ion) and (ion and neutral) species. We demonstrate the feasibility of this technique for the prototypical case of carbon tetrachloride, but this method is generally applicable as shown for nitromethane.