Abstract: | 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. |