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Analysis of the Raman spectral shape in α -AgI

1983; American Physical Society; Volume: 28; Issue: 12 Linguagem: Inglês

10.1103/physrevb.28.7269

1095-3795

E. Cazzanelli, A. Fontana, G. Mariotto, V. Mazzacurati, G. Ruocco, G. Signorelli,

Quantum Dots Synthesis And Properties

In this paper we present a detailed analysis of the Raman spectral shape of $\ensuremath{\alpha}$-AgI crystals as a function of temperature up to 450\ifmmode^\circ\else\textdegree\fi{}C. With the use of a polarizability model based on the charge-induced dipole mechanism, which was already introduced to explain depolarization ratios and integrated intensities, all the spectral features from 0.8 to 250 ${\mathrm{cm}}^{\ensuremath{-}1}$ are assigned to the iodine dynamics (acoustical and optical phonons), in agreement with inelastic-neutron-scattering data. Hence we predict that the central line originating from ${\mathrm{Ag}}^{+}$ diffusive motions must be confined to the frequency region below 0.8 ${\mathrm{cm}}^{\ensuremath{-}1}$. Some suggestions on the phonon branches are qualitatively derived from the temperature dependence of the spectral shape.