Dissociative electron attachment to methane probed using velocity slice imaging

The velocity slice imaging technique is used to obtain the kinetic energy and angular distributions of H⁻ and CH^-₂ ions formed by dissociative electron attachment (DEA) to methane. The data show two distinct anion states in the broad peak between 8 and 12 eV with the lower energy one undergoing two-body fragmentation, while the higher energy one undergoing a three-body fragmentation. The dissociation process is seen to be influenced by the Jahn–Teller effect similar to that seen in methane cation and its neutral counterpart