Molecules’ vibrations linger longer than thought

Solid surfaces are common sites of molecular reaction: gas molecules congregate there and react, for example on many solid catalysts. But a new study claims that such reactions might be more influenced by the vibrational state of the incoming molecules than has been thought. When a molecule sticks to a surface, previous studies have suggested that its vibrational energy will very quickly equilibrate: if it has excess energy, that will be dissipated into the surface within a few picoseconds (10^-12s). But Alec Wodtke of the University of Göttingen in Germany and his co-workers report that vibrationally excited carbon monoxide molecules adsorbed on a gold surface will retain that excitation for a surprisingly long time – up to hundreds of picoseconds.¹