Theoretical confirmation of the e.s.r. spectrum of the ethane cation

A C2h structure of the ethane cation, with a ‘normal’ C–C bond length, has been found as a minimum in the MP2/6-31G* potential energy surface, the isotropic hyperfine coupling constants for this structure, calculated using an accurate configuration interaction method, being in good agreement with the experimental e.s.r. spectral data reported by lwasaki et al.