Nuclear magnetic resonance spectroscopy surface species

In gas-phase reactions catalyzed by a solid surface, characterization of the chemisorbed species that are principally covering the surface can nowadays be made relatively easily by means of techniques such as IR and Raman spectroscopy, EELS, radioisotope labeling of reagents, and in some cases by nuclear magnetic resonance (NMR), electron spin resonance (ESR), and ESCA spectroscopies. In many cases, thermal desorption spectroscopy can be usefully applied to deduce indirectly the nature of species, and their distribution of energies of adsorption, that may have been strongly chemisorbed on the catalyst originally. 

A variety of spectroscopic techniques, however, are of value to determine the local bonding and, occasionally, oxidation states of various ions. Frequently, they can perform satisfactory quantitative analysis or estimates as well. Adsorption, emission, and Raman spectroscopy operating from the UV through the IR region of the spectrum can provide such information. These optical spectroscopies can be performed in either a transmission or surface-scattering mode based on the thickness and absorption properties of the specific sample. Nuclear magnetic resonance (NMR), Mossbauer spectroscopy, and electron spin resonance techniques are some other forms of spectroscopy frequently used to determine local bonding and oxidation states of specific species, primarily in the bulk rather than on the surface. These methods are limited to particular atoms or ions and are not universally applicable. 

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