Solvent effects in DFT calculations

Density Functional Theory (DFT) has proved to be an efficient and economical tool for the investigation of a variety of molecular properties. However, even with today's most powerful computers, the applicability of DFT is in fact limited to gas-phase studies and processes in small clusters of molecules. This constitutes a severe limitation, since many interesting chemical processes occur in condensed phase. To fill this gap, in the last years theoretical studies of molecular structure in condensed phase became increasingly popular and different approaches were developed. The two most commonly used schemes have been continuum salvation models and coupled potential methods. In continuum salvation models, the solvent is treated as a structureless dielectric continuum. On the other hand, in coupled potential methods the solvent molecules are treated explicitely using classical mechanics, while the solute is treated quantum-mechanically. The success in the applicability of these schemes is intrinsically related to the role of specific solute-solvent interactions. Applications to the study of tautomeric equilibria and spectroscopic and structural properties of inorganic complexes will be presented to illustrate the advantages and limitations of the two methodologies