A field ionization and collisionally activated dissociation/charge stripping study of some [C₉H₁₀]^+˙ ions

The extent of isomerization of [C₉H₁₀]^+˙ ions, with lifetimes of approximately 10⁻¹¹ and 10⁻⁶ s has been investigated using field ionization, collisionally activated dissociation and charge stripping techniques. The [C₉H₁₀]^+˙ ions which were investigated included the molecular ions of α‐methylstyrene, β‐methylstyrene, o‐methylstyrene, m‐methylstyrene, p‐methylstyrene, indan, cyclopropylbenzene, allylbenzene and the product of water loss from 3‐phenylpropanol. The field ionization spectra of all the C₉H₁₀ hydrocarbons were different indicating that isomerization to a common ion structure had not occurred to a measurable extent for ions with lifetimes of approximately 10⁻¹¹ s. Collisionally activated dissociation and charge stripping results indicated that most of the [C₉H₁₀]^+˙ ions continued to maintain unique ion structures (or mixtures of structures) at ion lifetimes of 10⁻⁶ s. Possible exceptions are the [C₉H₁₀]^+˙ ions from allylbenzene and cyclopropylbenzene which gave indistinguishable collisionally activated dissociation and charge stripping spectra.