Reactivity bands in atom--molecule collisions. IV. Coplanar and 3D studies of T+HT

The system T+HT, which showed collinear reactivity bands for T+HT→TH+T, is studied in 1D, 2D, and 3D for all possible orientations. The energy range is 0--2 eV (c.m.). Two and three dimensional Monte Carlo studies show no evidence of bands in the total reaction probability. Coplanar reactivity maps are analyzed to explain why the bands disappear. It is shown that the region leading to multiple collisions occupies a very narrow portion of the total configuration space available to reactants. This region is masked by the large reactivity for nonlinear orientations. Some systems which may show more persistent banding effects are proposed