Local structure and local symmetry in dilute solutions

摘要

This paper presents a novel application of symmetry, namely to the analysis of the structure induced in a solvent by the presence of the solute molecules. The method combines symmetry projection operator techniques with the concept of local high-symmetry sites within the solute molecule so as to generate families of symmetry adapted radial distribution functions (SARDFs) that are designed to highlight the structuring effect of the solute on the solvent. The technique is simple to implement, and provides significant new information that is not available from the more conventional methods of analysis. As illustrative examples, the SARDFs are used to examine the solvation structure around cyclic ketones in organic solvents, and around tert-butanol in water. In the latter case, the method produces clear evidence that structuring of the solvent is maximised when hydrogen-bonding interactions between the solute and solvent are of intermediate strength.