Effect of location of energy barrier on the product alignment of reaction A+BC

The trajectory calculations of heavy heavy-light, light light-light, heavy light-light, and light heavy-light mass combination reactions on attractive and repulsive potential surfaces have been carried out to study the dependence of the product rotational alignment on collision energies; The calculated results for heavy heavy-light mass combination reaction are compared with the predictions from the constrained product orbital angular momentum model. The final rotational angular momentum was found to be perpendicularly polarized with respect to the reagents' relative velocity vector on either attractive or repulsive potential surface. There is similar behavior of the product rotational alignments as a function of collision energies for heavy heavy-light and heavy light-light reactions, i.e., the more anisotropic the distribution of the product rotational angular momentum vector is, the higher the collision energies are, whether the potential surface is attractive or repulsive. However, the calculations for light light-light mass combination reaction predict that the product rotational alignments depend strongly on collision energies for an attractive potential surface, but this behavior is not observed on the repulsive potential surface. For light heavy-light mass combination, the product rotational alignments hardly depend on collision energies on both potential surfaces. (C) 1996 American Institute of Physics.