Several fragmentation reactions of ethylene were investigated by AM1 direct classical trajectories. Product yields were computed for ethylene and several deuterated derivatives at two excitation energies (193 and 157 nm). The atomic elimination channel is favoured as the energy increases, and hydrogen scrambling is found to be an important process at the energies of study, which contrasts with the mechanisms proposed up to date. The computed product yields are in better agreement with experiment than are previous RRKM calculations. The results suggest that the dissociation of ethylene occurs at, on near, the statistical limit, which disagrees with previous conclusions. (C) 2002 Published by Elsevier Science B.V.