Dissociative photoionization dynamics in ethane studied by velocity map imaging

We have studied the dissociative ionization of ethane from 12.0 to 12.8 eV using velocity map imaging with synchrotron radiation. We obtained translational energy release distributions and angular distributions for the C2H4+ product. The translational energy distributions are consistent with a ∼0.6 eV barrier to H2 elimination in the ethane cation, while the angular distributions are characterized by a limiting anisotropy parameter of β=−0.3. Theoretical calculations predict a lower anisotropy; possible reasons for the discrepancy are considered.