The structure of adsorbed molecules

Electron and X-ray diffraction techniques now make it possible to determine the structural parameters of molecules adsorbed on single crystal metal surfaces in a straightforward way. Moreover, scanned energy mode photoelectron diffraction and diffuse low energy electron diffraction also provide access to adsorption layers that do not show long range order. Even the scanning tunnelling microscope can deliver some degree of quantitative information, in that adsorption site determination is now possible. Recent examples of the analysis of the structure of adsorbed molecules by these techniques include diatomic molecules and associated coadsorption systems, molecular fragments created in simple heterogeneous reactions and hydrocarbons.