Kinetics of electron impact ionization and ion-molecule reactions of pyridine

Dissociative ionization of pyridine by electron impact is investigated using Fourier transform mass spectrometry (FTMS). Absolute total and partial ionization cross-sections are measured as functions of electron energy in the range of 10–200 eV. The parent ion and 15 fragment ions are observed, with the total cross-section reaching a maximum of 1.5 × 10−15 cm2 at ∼90 eV. Four important ions generated at 50 eV electron energy, C5H5N+, C4H4+, C4H3+, and C4H2+, are found to react with pyridine via mechanisms of charge transfer and proton transfer. C4H4+ also undergoes condensation with pyridine followed by H elimination.