Ion molecule reactions in vinyl fluoride by photoionization. Effects of vibrational excitation on major reaction pathways

Abstract

Photoionization methods have been used to study the reactions of the molecular ion in vinyl fluoride to yield the ionic products C 3 H 3 F{, C 3 H 4 F+, and C 3 Ht. Quantitative measurements are reported of the effect of the vibrational state of the reactant ion on the product distribution and overall reaction cross section. Reaction cross sections for all three channels decrease with reactant internal energy. The effect on the reaction pathway producing C 3 H 3 F{ is especially pronounced, with 0.18 eV of vibrational excitation being sufficient to reduce the reaction probability by 75%. Deactivation of vibrationally excited reactant ions competes with the reaction and is shown to be an efficient process.

Electron‐bombardment matrix isolation and PEPICO studies as complementary techniques in ion chemistry: an FTIR study of the decomposition of the vinyl fluoride cation

“…The complementarity of these two methods arises from the fact that the mechanism of ionization for the EB‐MI results yields vibrationally hot VF radical cation via: in a manner that is similar to photoionization at 15.8 eV. In both cases, the ionization leaves the initially formed ion with a net internal energy near 5.44 eV, corresponding to IP(Ar)—IP(VF) 18–20. According to the PEPICO results, a VF cation with 5.44 eV excess internal energy decomposes entirely, with < 10% relative ionic abundance of the parent ion in the breakdown curve 4.…”