The structure of expanded mercury

The structure of expanded mercury along its liquid-vapour coexistence curve has been studied in detail by applying the reverse Monte Carlo modelling technique to the x-ray diffraction data of Tamura and Hosokawa (Tamura K and Hosokawa S 1994 J. Phys.: Condens. Matter 6 A241). The models suggest that as the density decreases there is an initial change from a more close-packed to a less close-packed structure. Whilst most atom pairs retain the same near-neighbour distance, of about 3.0 Angstrom, a few change to having a slightly larger neighbour distance of about 3.7 Angstrom. At the lower densities many atoms have a very low coordination, indicating that they are on the edges of clusters, or on 'pathways' between clusters

Changes in the short-range order of gallium on melting and supercooling

Neutron diffraction has been used to study the diffuse scattering of gallium as it was heated from solid to liquid through the melting point, and then cooled from liquid to supercooled liquid. Little evidence was found of a pre-melting effect. A difference was observed in the rate of change of the diffuse scattering between the liquid and supercooled states from a slightly impure sample, but a high-purity sample showed little change in structure between +33 and -13.1 degrees C. Reverse Monte Carlo analysis has been applied to the supercooled liquid, confirming that its structure is very like that of the beta-phase