Shape resonances in the photionization spectra of free and chemisorbed molecules

This chapter summarizes recent experiments concerned with shape resonances in free diatomic molecules and shows how this knowledge can be used in surface physics to extract information otherwise difficult to obtain. Discusses shape resonances in chemisorbed molecules. Finds that many of the properties of free molecules are retained after chemisorption, and that it is possible to perform much more accurate theoretical calculations for free molecules than for the molecule surface complex. Points out that resonance excitations have been observed in the vibrational spectra in electron-molecule scattering of weakly bound (physisorbed) species