Study on dynamic properties of molten noble metal halides by sound absorption

Abstract Sound absorption was measured for molten AgBr–AgI mixtures to investigate the relation between dynamic properties and chemical ordering. The sound absorption for molten AgI shows a large value just above the melting temperature, and then decreases with increasing temperature. The sound absorption for molten AgBr–AgI mixtures increases with temperature from the melting point, shows a maximum around 600 °C, and decreases with increasing temperature. The frequency dependence of the sound absorption for molten AgI was also measured, and the relaxation time and relaxation strength are evaluated from the observed data by assuming a single Debye-type relaxation process. The evaluated relaxation time and relaxation strength are about 5.0 ns and 1.9×10 −3 . This relaxation time corresponds to a relatively slow motion compared with atomic motion, which may suggest a cooperated diffusive motion.