Raman spectra of Ag2HgI4were collected over the temperature range 8ndash;470thinsp;deg;K. The ordered phase of Ag2HgI4exhibits strong temperature dependent damping of the 85 cmminus;1mode. The reduced Raman spectra of the disordered phases of both Ag2HgI4and Cu2HgI4are found to be temperature dependent. This unusual temperature dependence is attributed to the combined influence of anharmonicity, multiphonon processes, and the correlation time for ion hopping. An estimate of the latter was obtained from the line broadening data. Based on polarized scattering data obtained on very small crystals, symmetry assignments are made for some of the Raman bands of Ag2HgI4.
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