Existence of an exceptional reaction pathway for H3+ formation observed in collision-induced dissociation of methane ions at 1000 eV.

Dissociation of CH4+ ions at 1000 eV induced by collision with Ar atoms was investigated by measuring the kinetic energies of the ionized fragments. At small scattering angles, including zero, H+, H2+, H3+, CH3+, CH2+, CH+, and C+ fragments were observed. The attractive part of the potential in the CH4+-Ar collision system played an important role in the formation of the ionized fragments. Rainbow scattering, leading to a large scattering cross section, was shown to be responsible for the increased formation of H3+. It is proposed that on collision-induced dissociation of CH4+, its three hydrogen atoms, which form a triangle, simultaneously react and move together to form H3+. [ABSTRACT FROM AUTHOR]