Structural studies of water and other hydrogen-bonded liquids by neutron-diffraction

The structural characteristics of hydrogen-bonded liquids may be studied by neutron diffraction. A brief review of the experimental techniques is given with particular emphasis on H/D isotope substitution and temperature difference techniques. These methods are illustrated with reference to recent work on water in its normal and supercooled liquid phases. The temperature variation is linked to the behaviour of the hydrogen bonds and the evolution towards the continuous random network of amorphous ice. A brief report is made for some other hydrogen-bonded liquids, contrasting the strong correlations in hydrogen fluoride which are not well understood with the study of methanol which gives good agreement with computer simulation results. Formic acid has also been investigated and novel techniques used in the analysis of the H/D datasets. The review ends with an overview of current issues and a consideration of future developments.