Dynamics of proton collisions with acetylene, ethylene and ethane at 30Â eV

► We study the collision dynamics of proton with C2Hm (m = 2, 4, 6). ► The nature of target ionization at 30 eV is electron capture. ► The proton exchange and the collision-induced dissociation process are studied in details. ► The complex structure of the scattering angle results from the force which the projectile is subjected to. ► The fact that calculated ionization cross sections increase with C-C bond length arises from the C-C bond effect.