Jump to Main Content
Real-Time Observation of Molecular Motion on a Surface
- Backus, Ellen H. G., Eichler, Andreas, Kleyn, Aart W., Bonn, Mischa
- Science 2005 v.310 no.5755 pp. 1790-1793
- platinum, spectroscopy
- The laser-induced movement of CO molecules over a platinum surface was followed in real time by means of ultrafast vibrational spectroscopy. Because the CO molecules bound on different surface sites exhibit different C-O stretch vibrational frequencies, the site-to-site hopping, triggered by excitation with a laser pulse, can be determined from subpicosecond changes in the vibrational spectra. The unexpectedly fast motion--characterized by a 500-femtosecond time constant--reveals that a rotational motion of the CO molecules, rather than pure translation, is required for this diffusion process. This conclusion is corroborated by density functional theory calculations.