Isomerisation of hydrocarbon ions:II—Octenes and isomeric cycloakanes: Acollisional activation study

[C 8 H 16 ] +. molecular ions from alkenes and cycloalkanes differing in their skeletal con‐figuration do not in general isomerise completely to a common structure, except for the molecular ion of n ‐propylcyclopentane, the structure of which is identical to that of the normal octene ions. In contrast, decomposing [C n H 2n−1 ] + fragments are completely or almost completely isomerised after a lifetime of a few μs.