A novel scheme for probing mode-specific proton transfer in proton-bound homodimers: vibrational predissociation and ab initio study on CH5+·CH4

A novel experimental scheme for probing mode-specific proton transfer in proton-bound homodimers based on the vibrational predissociation spectroscopy combined with the techniques of mass-selected detection and isotope substitution is described. Its application to CH5+·CH4 suggests that rapid, non-mode specific proton transfer occurs when three C–H stretch modes are excited. To explain the experimental result, the transition state and the minimum energy path (MEP) for proton transfer in CH5+·CH4 are further characterized by ab initio method.