Variable-temperature ion mobility time-of-flight mass spectrometry studies of electronic isomers of Kr²⁺ and CH₃OH^+• radical cations

Preliminary results from a liquid nitrogen-cooled ion mobility (IM) orthogonal-time-of-flight (o-ToF) mass spectrometer applied to the separation of electronic isomers of Kr²⁺ and methanol radical cations (conventional and distonic) are presented. Ab initio calculations were used to estimate the energies and energy barriers to interconversion between conventional (CH₃OH^•+) and distonic (CH ₂^•OH₂⁺) radical cations. In addition, computations and experiments are used to compare ion-neutral collision cross-sections for CH₃OH^•+ and CH ₂^•OH₂⁺ radical cations and suggest that the mobility separation is achieved by ion-neutral interactions between ions and neutral buffer gas.