Effects of Bending Excitation on the Reaction of Chlorine Atoms with Methane

Bent up energy: Contrary to intuitive expectations, excitation of the low-frequency CH4(ν4=1) bending motion enhances the cross section for reaction with Cl atoms by a factor of two or more. This enhancement, which is constant over the collision energy range 0.12 eV to 0.26 eV, implies that shearing motion, in addition to stretching motion, can facilitate CH bond cleavage in this direct abstraction reaction (see scheme; green Cl, purple C, gray H).