DYNAMICS OF ETHYLENE PHOTODISSOCIATION FROM ROVIBRATIONAL AND TRANSLATIONAL ENERGY-DISTRIBUTION OF H-2 PRODUCTS

The dynamics of H-2 elimination from ethylene was studied via a pump and probe technique utilizing an ultrahigh resolution vacuum ultraviolet laser system. H-2 product internal and translational energy distributions were obtained for the photodissociation at 193 nm. The distribution of energy in H-2 product from the dissociation of (1,1)-dideuteroethylene is also presented. Two separate H-2 elimination channels are inferred: a 1,1 elimination producing the vinylidene radical and a 1,2 elimination producing the acetylene molecule. Differences between the vibrational, rotational, and translational energy distributions for these two channels are discussed and correlations between product internal and translational energy are presented. A comparison with ab initio calculations of the transition state configurations for these processes is made. We suggest that the H-2 elimination process may be nonstatistical in nature. The D atom elimination from C2D4 was examined and kinetic energy distribution for this product measured.