Mass analysis of high-Rydberg fragments produced by electron impact on ethane by use of a pulsed-field-ionization technique

A new apparatus to analyze the mass of high-Rydberg (HR) species produced by electron impact has been developed with the help of a pulsed-field-ionization (PFI) technique and applied to ethane. The intensity distribution of the HR species produced from ethane agreed well with that of the corresponding ions when PFI was carried out on a delay time of 2.0 μs after excitation. The intensity distribution, however, changed with an increase of the delay time. These findings demonstrate that the core ion model holds for the dissociation of HR ethane and that the lifetimes of the HR species are different.