Infrared Spectroscopy of Surfaces

Abstract

Vibrational spectroscopies are sensitive probes of molecular structure of adsorbed species on solid surfaces. Infrared spectroscopy has been used extensively to examine the species adsorbed on metal oxides, primarily silica and alumina. Adsorption on metals was initially studied with infrared spectroscopy by supporting small metal particles on high surface area silica or alumina. More recently, adsorbates on metal single crystals and films have been studied with reflection infrared spectroscopy. This chapter reviews the application of infrared spectroscopy for characterization of adsorbed species on surfaces. Infrared spectroscopy of adsorbed species can be obtained by attenuation of transmitted light through a sample that is adequately transparent in the spectral region of interest. Infrared spectra of species adsorbed on metals and semiconductors can be obtained by absorption of radiation reflected from the surface. Temporal evolution of spectra is often used to determine reaction kinetics.