Micro-Raman Spectroscopy of Crystal Lattice Chemistry

Topochemistry is a discipline within solid-state chemistry in which the chemical reaction is localized to the crystal surface of one of the reactants. In general, this means that the crystalline reactant undergoes a chemical transformation induced either by exposure to another reactant or light of a suitable wavelength to cause a photochemical reaction. Recently, the term crystal engineering has been used more frequently than topochemistry. This class of chemistry has allowed chemists to produce reaction products that otherwise could not be generated under any other conditions. Furthermore, it has led to the engineering of thin-film structures and waveguides whose chemical and physical properties differ to some degree from those of the reactant crystal. Micro-Raman spectroscopy is ideally suited to characterize and spatially resolve the chemical and physical changes that occur in topochemical reactions, particularly in thin films and waveguides.