A neutron diffraction and isotopic substitution measurement of the structure of liquid Cu2Se

Abstract

The partial structure factors and pair distribution functions of liquid Cu₂Se have been determined by neutron diffraction with isotopic substitution. The structure shows characteristics typical of those of an ionic 2:1 melt consisting of Cu⁺ and Se^2- ions with the cations moving through a more ordered Se^2- sub-structure. A detailed comparison has been made with recent results obtained for liquid Ag₂Se. The structure is similar although there is no evidence of the double peak structure in the cation-cation partial structure factor, S_CuCu(Q), as has been found in S_AgAg(Q) for liquid Ag₂Se and, to a more limited extent, for liquid Ag₂Te. There is also less order in the Se^2- sub-structure based on a comparison of S_SeSe(Q) and the Bhatia-Thornton concentration-concentration structure factor, S_CC(Q), for the two liquids.