How do the structures of polyatomic molecules affect their reaction dynamics?

The reactions of Cl atoms with three organic ethers, dimethyl ether (CH3OCH3), oxirane (c-C2H2O) and oxetane (c-C3H6O) provide an opportunity to study the effects of different molecular structural motifs on the chemical dynamics. The rotational excitation of the nascent HCl reaction product has been measured for all three reactions, and the results are compared with direct dynamics trajectory calculations that allow mechanisms to be visualized with the aid of trajectory animations. Reaction of oxirane, a strained, three-membered ring compound, gives rise to HCl that is markedly rotationally cooler (T-rot = 168 7 K) than the products of the two other reactions (T-rot = 418 +/- 25 K for Cl + dimethyl ether and 399 +/- 23 K for Cl + oxetane). Possible reasons are discussed in terms of the reorientational dynamics of the polar HCl and organic radical products in the post-transition state regions of the reaction potential energy surfaces.