A determination of the structure of liquid Ag₂Se using neutron diffraction and isotopic substitution

The partial structure factors and pair distribution functions for liquid Ag₂Se were meastured using the method of neutron scattering and isotopic substitution. The results show many features which are consistent with an ionic melt in which small Ag⁺ ions move rapidly through a highly orderd Se^2- liquid sub-structure in a similar way to the motion of Ag⁺ in the fast-ion solid which exists prior to melting. The results are compared with recent molecular dynamics and ab initio molecular dynamics calculations, and the relative merits of the two simulation approaches are discussed in relation to the data.