Has anyone seen today’s issue of Science? There is a research paper by Shannon Yan and colleagues “Do Vibrational Excitations of CHD₃ Preferentially Promote Reactivity Toward the Chlorine Atom?” I had a difficult time following the authors – physical-molecular chemistry is not my strongest field, but nevertheless …

The study shows the energy of the moving molecules can unexpectedly promote a chemical reaction as effectively as the energy from within the chemical bonds. Until now, there has been a general assumption characterized as the Polanyi rules that the energy dynamics of reactions of small molecules with two and three atoms were simple – the vibrational energy of the bonds determines reactivity. However, a series of precisely controlled molecular collision experiments now challenges this model.

The P. Chem. scientist discovered that when CHD₃ collides with Cl atoms to form CD₃ and HCl, translational energy (produced by the movement of molecules in relation to each other) promoted the reaction as effectively as selective excitation of the C-H stretch vibration.

(DOI: 10.1126/science.1142313)