A DETERMINATION OF THE STRUCTURE OF LIQUID AG2SE USING NEUTRON-DIFFRACTION AND ISOTOPIC-SUBSTITUTION

The partial structure factors and pair distribution functions for liqu id Ag2Se were measured using the method of neutron scattering and isot opic substitution. The results show many features which are consistent with an ionic melt in which small Ag+ ions move rapidly through a hig hly ordered Se2- liquid sub-structure in a similar way to the motion o f Ag+ in the fast-ion solid which exists prior to melting. The results are compared with recent molecular dynamics and ab initio molecular d ynamics calculations, and the relative merits of the two simulation ap proaches are discussed in relation to the data.