A molecular dynamics simulation of premelting effect in AgBr

The “premelting effect” in AgBr was simulated by the Molecular Dynamics (MD) technique. At a temperature about 150 K below the melting point, considerable increase of cation mobility was observed, DAg+ values being well above 10−6 cm2/s. Analysis of the Ag+–Ag+ radial distribution functions shows that upon approaching the melting point, long-range order in the cation sublattice is lost, which resembles transition to a superionic state. The results obtained agree well with the effect of ionic conductivity increase previously observed in the same temperature range. The premelting of AgBr has features similar to that observed in MF2 (M=Ca, Ba, Sr, Pb) family of anion conductors.