IMPACT OF NEUTRON-SCATTERING ON THE STUDY OF WATER AND AQUEOUS-SOLUTIONS

Neutron scattering is making a major impact on our physical and chemical understanding of water structure in aqueous solution. In combination with the technique of isotope substitution it can probe, via the partial pair correlation functions of the system, both the structural aspects of the water itself in solution and the correlation of water molecules with individual dissolved ions and molecules. Moreover it can also investigate the way the solute species distribute themselves in solution. The use of the so-called first-order difference method to look at the hydration of inorganic ions in solution has already been widely reported in several previous reviews, so this account concentrates largely on recent advances in the application of the second order hydrogen-deuterium substitution method to the study of water under non-ambient conditions, and to the measurement of water structure in a variety of solutions and heterogeneous media. It is also shown how the same technique can be used to investigate the nature of solute-solute correlations in solution, and the way water organizes itself around organic molecules and ions in solution.