Slow dynamic properties of molten silver halides

• Published in: Journal of non-crystalline solids Vol. 353; no. 32-40; pp. 3169 - 3173
• Main Authors: Takeda, S., Nagata, Y., Kawakita, Y.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15-10-2007; Elsevier
• Subjects: Acoustic properties and phonons; Condensed matter: structure, mechanical and thermal properties; Electrical and electronic properties; Exact sciences and technology; Halide glasses; Lattice dynamics; Molten salts; Physics; Structure; Structure of associated liquids: electrolytes, molten salts, etc; Structure of liquids; Structure of solids and liquids; crystallography; Vibrational states in disordered systems; 61.20.Ja; Electrical and electronic properties; Halide glasses; Molten salts; 61.12.Ld; Acoustic properties and phonons; Structure; Acoustical phonons; Acoustic properties and phonons; Electrical and electronic properties; Halide glasses; Molten salts; Structure; Frequency dependence; 61.12.Ld; 61.20.Ja; Melting points; Structure relaxation; Relaxation time; Silver chlorides; Covalent bonds; Silver iodides; Lattice dynamics; Chemical bonds; Acoustic wave absorption; Ionic bonds; Liquid structure; Melts
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2007.05.154

The sound absorption has been measured for molten AgCl–AgI mixtures to investigate the relation between the dynamic properties and chemical bonding. The sound absorption for molten AgI shows a large value just above the melting temperature, and decreases with increasing temperature. The sound absorption for molten mixtures around the eutectic composition increases with temperature from the melting point, showing maximum value around 580°C, and decreases with increasing temperature. The frequency dependence of the sound absorption for molten AgI and mixtures are also measured, and the relaxation time and relaxation strength are evaluated from the observed data by assuming single Debye-type relaxation process. The evaluated relaxation time for molten AgI is about 9.0ns just above melting temperature and decreases slightly with temperature to about 6.4ns at 750°C. This relaxation time corresponds to a quite slow motion compared with the ordinary atomic one, and may suggest a structural relaxation of atomic association between ionic and covalent character. In the mixture around the eutectic region, evaluated relaxation time shows a rather complicated temperature dependence. Those values decreases slightly with temperature from the melting temperature, and have a minimum value around 600°C, and then slightly increase with the temperature.