PRIMARY PRODUCTS OF MULTI-PHOTON DISSOCIATION OF THE C2H4 MOLECULE IN AN INTENSE IR FIELD

A systematic investigation of C2H4 dissociation in an intense IR field with formation of C2 radicals has been carried out by the laser induced fluorescence method. It has been found out that C2 radicals are formed at ethylene pressures less than 0.1 torr without collisions and in the sense are the primary products of dissociation. The role of collisions at pressures of 0.1-4 torr can be explained by a rotational relaxation process at low vibrational levels of the C2H4 molecule. The rotational relaxation time has been experimentally estimated to be 20 ns torr. Various possible mechanisms of C2 radical formation are discussed. © 1979.