Surface spectroscopy, sample preparation chemical enhancements

The observation and understanding of SERS are clearly very important developments in the study of surface chemistry and surface physics. The combination of molecular information and extraordinary sensitivity provides a valuable probe of surface structure and behavior. Out of the broad study of SERS by both chemists and physicists have emerged several approaches to using SERS for chemical analysis. A common analytical situation involves preparation of a SERS active substrate by one of several methods, then exposure of the substrate to a liquid or gaseous sample. Subsequent Raman spectroscopy of the adsorbed layer provides the analytical signal, enhanced by whatever chemical or field enhancement is provided by the adsorbate-substrate interaction. The current and next section are not intended to address SERS substrates comprehensively, but several of analytical interest are described. 

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