PROBING THE NATURE OF MOLECULAR CHEMISORPTION USING RAIRS

Reflection absorption infrared spectroscopy has now established itself as a powerful and versatile technique for monitoring molecular adsorp tion at defined single crystal metal surfaces. This paper discusses th e success of the technique in providing a wide range of information, i ncluding the identification of hydrocarbon species and monitoring mole cular adsorbate-induced surface reconstructions. The use of IR spectro scopy in determining the nature of chemisorbed species is discussed in the light of recent structural investigations questioning the validit y of vibrational ''fingerprints''. Finally, the need for high resoluti on capability is demonstrated by new intramolecularly decoupled IR exp eriments which allow individual types of CH bonds in complex hydrocarb ons to be identified.