Such information is used to devise models and verify mechanisms in heterogeneous catalysis and molecular epitaxy and may aid development of molecular electronics and sensors. It should capture the imagination of anyone who has ever wanted to visualize an atom and the construction of molecules. Starting with a pristine silver specimen, Ho and Lee prepare the platform on which chemical reactions will be carried out by delivering to the silver surface trace quantities of iron atoms and carbon monoxide molecules. Displaying angstrom-scale deftness, the Cornell researchers then pick up a single CO molecule and position it over an isolated iron atom. Images reveal changes in the appearance of the atomic landscape as bonds are formed and molecules are constructed.
Vibrational measurements identify and characterize reactants and products quantitatively.
Doing vibrational spectroscopy with an STM has been a Holy Grail of sorts for quite some time. A procedure that combines vibrational measurements with an STM's atomic-scale spatial resolution would enable scientists to study vibrational spectra of single molecules, he adds. The technique, known as inelastic electron tunneling spectroscopy, relies on small, sharp changes in an electrical current that flows between an STM tip and an adsorbed molecule. Variations in current depend on the energy of tunneling electrons. A signal is observed when the energy of the electrons matches the energy of a molecular vibration.